Apparently Qatar has a single ISP, Qtel, with a single IP address shared by the entire country. Wikipedia has blocked that IP address for anonymous edits, but is allowing users of that IP address with actual Wikipedia accounts to continue to edit articles. There’s one problem, though. You can’t create an account if you enter Wikipedia from that IP address. It’s a bit of a Catch 22, and users will be forced to either use a proxy to enter the site (many of which are also banned), or simply stop editing altogether.
One answer to this problem is for Wikipedia to end anonymous editing and force user accounts on anyone that wants to contribute.
Digg blocks accounts based on IP address, too. I wonder if they’ve also banned Qatar.