Most people in the world can remember where they were and what they were doing when they heard about the planes terrorists flew into the World Trade Center in New York and the Pentagon in Washington, DC. This Thursday marks the seventh anniversary of the disaster, and since then a global "war on terror" has been waged -- but not won.

With NATO support, the US has toppled the Taliban regime in Afghanistan and established a new government, but not stabilized the country. A second war was started in Iraq with 9/11 as a justification -- but on false premises, as most of the world knows now and many people already understood in 2003.

Most of the world now has a new understanding of "security." Global terrorism of the sort practiced by al-Qaida finds targets that are not always easy to comprehend: a Danish embassy in Pakistan, nightclubs on Bali, trains in London and Madrid, wedding parties in Jordan, a synagogue in Tunisia, a British bank in Istanbul.

To protect themselves, Western as well as non-Western states have passed new laws, some of them draconian. The United States set up a prison at Guantánamo Bay which has yet to be dismantled.

The CIA has kidnapped and transported terror suspects all over the world, including people who weren't especially suspect and have long been proved innocent. Arab nations have signed dubious extradition treaties to move terrorist suspects back and forth. Russia and China use the "war on terror" for their own purposes -- to declare Chechens and Uighurs potential terrorists, for example. The debate over torture, once thought to be settled in civilized nations, has enjoyed an unexpected and in some ways ignoble renaissance.

And al-Qaida?

Al-Qaida is not beaten. Osama bin Laden and Ayman al-Zawahiri are still at large. A number of high-ranking members of the organization have been killed or arrested, including Khalid Sheikh Mohammed, Ramzi bin al-Shibh and others. But terrorism hasn't stopped. Al-Qaida has retreated in Iraq, perhaps, but in Pakistan as well as North Africa, it has gained influence and space.

But there is no single, clear image of al-Qaida or its current status. It has changed from an organization of militias into something nobody recognizes. Is it more of a movement? Are al-Qaida's capabilities weaker than before, or is another 9/11 still possible? Are there fewer members of al-Qaida now, or more?

For the seventh anniversary of 9/11, SPIEGEL ONLINE has asked seven renowned terrorism experts from seven different countries for their opinions of the threat al-Qaida still poses. They are all influential analysts, authors and observers of the global jihad movement. They agree on many things, but disagree on such basic principles as the network's future goals and the success of Western measures against terrorism.

Reuven Paz, Israel: "A Worldwide Model for Both Terrorism and Insurgency"

Looking back seven years since 9/11, it seems that the original al-Qaida, or Qa’idat al-Jihad, has managed to fulfill a great part of its short-range goals. The group’s leadership is still active and at large; it managed to turn Iraq into a worldwide model for both terrorism and insurgency; it shifts from Iraq quite successfully toward Afghanistan and West Pakistan, regained some power in North Africa, Somalia, and Yemen; and hot-wired the imagination of a growing class of self-radicalized Muslim youth. Above all, the use of martyrdom operations is still its most effective weapon in its efforts to achieve symmetry with the "enemy." A sense of the apocalypse is still the strongest element to inspire and mobilize many would-be terrorists.

Nevertheless, there was no progress in achieving its main long-term goals. Not one Muslim government in general, or Arab government in particular, was toppled or even much affected by jihadist activity. So far, after seven years, the world in general and the Muslim world in particular has learned to live with the jihadist phenomenon. Al-Qaida and the messages of global jihad remain a tiny minority in the enormous Muslim world. Its sting may be felt almost anywhere in the world, but it is nothing but a sting. A small war in Georgia may shake up world geo-politics more than a major al-Qaida attack.

Is the organization stronger than it was seven years ago? Yes, because it is still highly motivated, has a free hand in spreading its doctrines and messages through the Internet and can still mobilize support. The rest of the world has not yet found efficient answers to confront this high motivation. Al-Qaida, directly or through loyal proxies, may yet repeat the disastrous attacks of 9/11, with even greater effect or damage. It is not likely to happen on American soil, however, but against global American and Western interests -- probably oil fields or international aviation. Through a "war of the minds," which will continue for a long while, al-Qaida can inflame hatred and exaggerate imaginary victories, even kill and maim people, mostly Muslims, but it can't establish real power, even in the Muslim world. The latter is still not ready for revolution or major change.

It seems that al-Qaida's main transformation as a movement is toward "soft power" from the "hard power" of terror and violence. Yet we should take it seriously, because it might become a source of power in the far future, primarily among Muslim communities outside of the Muslim world, where the search for change is vivid.

Reuven Paz directs the Project for the Research of Islamist Movements in Herzliya, Israel.

Rohan Gunaratna, Singapore: "An Alliance of about 40 Jihad Groups"

Seven years after al-Qaida attacked America's most iconic landmarks, the US, its allies and friends face a sustained threat from the global jihad movement. Led by Osama bin Laden and Dr. Ayman al-Zawahiri, its constituents are al-Qaida, its operationally connected associated groups and its ideologically driven homegrown cells. To enlist Muslim territorial and émigré support, al-Qaida frames the fight as a struggle to protect Muslims and defend Islam. By building an alliance of about 40 jihad groups and by ideologically indoctrinating Muslims, al-Qaida has built a movement to fight for Islamic states. The percentage of Muslims advocating, supporting and participating in violence is a tiny minority, but it is sufficient to maintain a campaign of extremism and terrorism. But the bulk of Muslims don't participate in this contest between the extremists and government.

Current American strategy is oriented toward lethal and kinetic force. It is not suitable to fight the jihadism. The US-led Global War on Terrorism (GWOT) is focused on operational counterterrorism -- catch, kill, disruption. The jihadists have a higher potential to replenish their human losses and material waste, and fight back. By improving intelligence and operational capabilities, governments can locate, identify and target both jihadist support and operational infrastructures. Nonetheless, by targeting these physical infrastructures, it is not possible to end extremism.

For strategic victory, both the physical and conceptual infrastructures of the jihadists must be dismantled. To meet this challenge in conflict zones, government must mobilize and integrate the military with essential elements of national power. In conflict zones, civilian agencies alone cannot operate and military power alone cannot succeed. There is no other option but to think creatively and build new capabilities across government agencies and their partners. Furthermore, the West alone cannot fight this campaign. Yet only Western countries have the global reach, staying power, resources and discipline to develop and implement an international grand strategy to fight the second phase.

This phase will be a long and enduring campaign, and it will require, first, a greater understanding of the operational environment, especially the threat, and also a greater capacity among foreign governments to engage the affected population and fight the enemy.

Rohan Gunaratna is head of the International Center for Political Violence and Terrorism Research in Singapore.

Guido Steinberg, Germany: "Trend toward a Leaderless Jihad"

Al-Qaida was weakened by the loss of its base in Afghanistan in 2001, but a broader, more global network of jihadi groups has risen in the meantime that also includes an ever-growing role for radicalized European activists.

There are three trends, and the biggest danger would involve a bundling of all three. Al-Qaida is gaining strength in Pakistan, but only has individual contacts to individuals in Europe. Young people in Europe aren't able to operate effectively without terrorist training.

This is the reason the attacks over the last few years have been less spectacular than the attacks of September 11. But if a resurgent al-Qaida (or al-Qaida in the Islamic Maghreb, based in Algeria) manages to win more European recruits who can organize and plan attacks largely on their own, then larger attacks will be a risk in Europe. The large number of European youths who have been travelling to Pakistan for training over the last several years is a clear warning sign.

An overview of the three main trends:

1) The organization known as al-Qaida, under the leadership of Osama bin Laden and his deputy Ayman al-Zawahiri, remains important. Since 2005 it has been resurgent in Pakistan and has renewed old ties with the Taliban. It is still weaker than it was in 2001, but it's having more influence over terrorist plots in southern Asia and beyond. The attacks in London in 2005, the plans for attacks on London-based flights across the Atlantic in 2006, and the preparations of the German-based "Sauerland cell" in 2007 can be traced back to a newly organized al-Qaida.

2) Al-Qaida's biggest success was forging ties with local groups in Iraq in 2004 and Algeria in 2007. The two groups operate individually from one another, but they give the impression that al-Qaida has a global reach. Members of both al-Qaida in Iraq and al-Qaida in the Islamic Maghreb have brought jihadism back to their Arab homelands. North Africa is now the main site for jihadist training in the region, and attacks are especially a risk in Morocco.

3) At the same time, in Europe, a trend toward "leaderless jihad" has started. Links between terrorist cells and larger organizations like al-Qaida are weaker than before. Local groups plan and organize with more independence, which means Islamic terrorism has become less predictable. This trend is known, rather fecklessly, as "homegrown terrorism." It suggests a European brand of jihad, marked by an ever-broadening social base. New groups of young Pakistani, Turkish and Kurdish terrorists have attached themselves to the more dominant Arab networks.

Guido Steinberg is a terrorism expert at the German Institute for International and Security Affairs in Berlin.

Fuad Hussein, Jordan: "Al-Qaida is Stronger Today"

I believe that there will be another attack like September 11 -- sooner rather than later and perhaps on an even greater scale. And that is due to the fact that the Washington-led "War on Terror" has increased the circle of enemies. It is no longer just al-Qaida and the Taliban, but all Islamist movements, even those that are less extreme than al-Qaida. This is increasing the hate towards America, which has already been fanned by the number of civilian victims as a result of the American operations in Afghanistan and Iraq.

I also believe that al-Qaida is stronger today than it was before Sept. 11, 2001. Before 9/11 there was just one single al-Qaida in Afghanistan, today there are several al-Qaidas in the world, for example in Iraq, in Saudi Arabia, in Yemen, in North Africa. And there are a few groups that have not even announced that they belong to al-Qaida because the leadership does not think the time is right yet.

From the al-Qaida that earlier planned an occasional attack here and there has emerged an al-Qaida that carries out daily attacks -- particularly in Iraq and in Afghanistan. Al-Qaida is therefore in the media every day. And that is exactly al-Qaida wants.

Apart from the new bases for operations, the most important change for al-Qaida since 9/11 is that it has achieved a permanent presence on the Internet, which is almost like another base. In any case, it makes up for the training and terrorist camps in Afghanistan.

The al-Qaida organization has in the meantime become a movement. Those who support al-Qaida will today launch their own attacks if they can and if they believe that it fits into al-Qaida's overall strategy. That means that al-Qaida is very difficult to fight, which increases the danger that it poses.

Fuad Hussein is a journalist and author ("Al-Qaida's Second Generation") based in Amman, Jordan.

Peter Neumann, United Kingdom: "Al-Qaida on the Defensive"

Al-Qaida is on the defensive, but the group has not yet been beaten.

Everywhere in the world, al-Qaida has lost support. Even radical Islamists are now debating about the logic (or illogic) of attacks against civilians. The worldwide fight against terrorism has also destroyed most of al-Qaida's support structure.

But the danger is (still) not gone. Al-Qaida has new training camps and safe havens on the border between Pakistan and Afghanistan. In Europe there are still thousands of radical Muslims who may not be "members" of al-Qaida but nevertheless support their ideas.

If experienced al-Qaida members in the Pakistani tribal areas have more success in training European radicals and bringing them into existing structures, then the risk of a new September 11 would be high. But if the status quo remains unchanged, for now, there will certainly be more tragic attacks -- even, eventually, in Germany -- but attacks on the order of the plots in London and Madrid, rather than those in New York and Washington.

Peter Neumann is Director of the Center for the Study of Radicalization and Political Violence in London.

Bruce Hoffman, USA: "Al-Qaida Has Re-Grouped and Re-Organized"

Al-Qaida has much to celebrate in 2008. Although still a shadow of its former pre-9/11 self, the movement has re-grouped and re-organized in the lawless border area along the Pakistan-Afghanistan border. It thus once again has a sanctuary in which it can train and operate (primarily in Pakistan’s Federally Administered Tribal Areas) and, moreover, is marshalling its forces to continue the struggle against the United States, which Osama bin Laden declared 12 years ago. A terrorist group like al-Qaida, which by now has survived for two decades, shows the determination, resilience and ability to overcome or obviate even the most consequential countermeasures of its governmental adversaries.

In this respect, the movement continues to pin its hopes and faith on some new, spectacular terrorist attack that will catapult al-Qaida back into prominence and put them back on an upward trajectory. In a year marking both al-Qaida's 20th anniversary and perhaps the most important American presidential race in recent decades, it would be rash to discount the threat that even a weakened, diminished al-Qaida poses. It is exactly when we are lulled into complacency and our defenses are down that al-Qaida will strike.

Bruce Hoffman is a professor at the Edmund A. Walsh School of Foreign Service at Georgetown University, Washington D.C.

Magnus Ranstorp, Sweden: "The West Still Finds it Difficult to Understand al-Qaida"

The British government recently described al-Qaida as a security problem but not a strategic threat. Al-Qaida does not have the sufficient quantitative or qualitative possibilities to completely shut down the functions of the society or the country. I agree. At the moment al-Qaida is a terrible annoyance that one has to live with but not a strategic threat -- at least as long as al-Qaida does not manage to get its hands on weapons of mass destruction or to paralyze the New York financial district with a dirty bomb.

Of course, al-Qaida is going to continue trying to do exactly that. And the al-Qaida leadership is still very influential, having forged strong ties with the Pakistani Taliban. On the one hand, al-Qaida is today somewhat weakened by the measures taken against it after 9/11 but also because the terror network has to increasingly justify its brutal deeds. On the other hand, there are clearly new al-Qaida branches and new regions where the network is gaining in strength, for example, in the Horn of Africa, Yemen or North Africa.

I assume that al-Qaida will surprise us with attacks in the future, attacks that we have not prepared for. Will they sink a ferry? Attack a chemical plant? The plans for an attack in London that were thwarted last summer -- and that would have destroyed seven passenger airlines -- show that al-Qaida is still contemplating ambitious targets.

And what is al-Qaida today? An organization, a network, a movement? Al-Qaida is all of these things. Some people try to put al-Qaida in one of these pigeonholes. But that doesn’t make sense, because al-Qaida functions and operates on all of these levels.

While the threat that al-Qaida poses is very real, the true danger when it comes to terrorism is, in my opinion, a very different one. It is the way in which terror influences our society: polarization, xenophobia, fear of migrants are the terrible aftereffects of terrorism and are a greater threat than the terror itself.

Even seven years after 9/11, the West sometimes finds it difficult to understand al-Qaida. Al-Qaida has no king who could be overthrown, no checkmate move that just has to be found. In the West we often think in these kinds of chess categories: linearly, structurally, the same way we used to always wage wars. Our idea of victory also derives from this way of thinking. However the Asian game "Go" would really be a more suitable model for the war on terror. In that game, it's not about establishing some kind of victory but, rather, about dominating the battle field.

Magnus Ranstorp is Research Director at the Center for Asymmetric Threat Studies (CATS) at the Swedish National Defense College.