This article about gang wars involving Pakistani immigrants in Denmark--while not related-reminds me that I haven't read anything about the reactions of Moslem enclaves in Europe to the wave of unrest in the Arab world.
We've seen unrest in these enclaves before. Why wouldn't the swelling anger in the Arab world not find fertile ground in Western Europe, where there are grievances aplenty to cite as reasons to riot and set cars on fire?
Not that these would be revolts that could take control. But it could add to the environment (complete with lots of television and Internet /cell phone footage) of unrest that could fuel what is going on in the Arab world.