UPDATE: This wire service report says the Turkish government banned YouTube today because of videos "insulting the founder of modern Turkey, Mustafa Kemal Ataturk." Snip:i have not been able to determine why yet, but youtube has been blocked in turkey by a court order. typing any youtube url while in turkey gives the following screen:
www.youtube.com sitesine eriÅŸim İstanbul 1. Sulh Ceza Mahkemesi'nin 2007/384 sayı ve 06.03.2007 tarihli kararı gereği engellenmiÅŸtir.
Access to www.youtube.com site has been suspended in accordance with decision no: 2007/384 dated 06.03.2007 of Istanbul First Criminal Peace Court.
interestingly, the ban seems to be browser specific, as youtube is still accessible thru firefox for some wierd reason. Youtube files which are embedded in other websites still are accessible as well.A quick websearch hasnt turned up anyone else covering this development so far... so i dont know if it is copyright law related, or if it is another enactment of the 301 law in turkey which is the political speech law that Orhan Pamuk and many other turkish authors and dissidents have been prosecuted under in the last years.
Paul Doany, head of Turk Telekom, Turkey's largest telecommunications provider, said his company had begun immediately enforcing the ban.Link. Kind of odd to see this happening when Turkey tourism ads have just started airing on CNN and other US television networks, part of a year-long, $120 million promotional effort. Perhaps the Tourism Ministry might try a new slogan in the next round of TV ads: "Visit Turkey and shut up.""We are not in the position of saying that what YouTube did was an insult, that it was right or wrong," Doany said in remarks to the state-run Anatolia news agency. "A court decision was proposed to us, and we are doing what that court decision says."
Doany said Turk Telekom would allow access to the popular video sharing site again if the court decision were rescinded. Access from Turkey might be possible through other service providers, he said.
Turkish youtubers, here is a collection of tips for routing around internet censorship from broken governments: Link to BoingBoing's "defeat censorware" guide.
UPDATE 2: Here's what internet users in Turkey see now when they try to access YouTube. Link to full-size (thanks Boor Rat)

i have not been able to determine why yet, but youtube has been blocked in turkey by a court order. typing any youtube url while in turkey gives the following screen:

Selim Gul.
its not blocked to himself ( erdoÄŸan ). We are did wrongs.bed word etc..
http://www.youtube.com sitesine eriÅŸim İstanbul 1. Sulh Ceza Mahkemesi’nin 2007/384 sayı ve 06.03.2007 tarihli kararı gereÄŸi engellenmiÅŸtir
it means is it
we r different nationality, we can wrongs.. and its blocked by ourselves.
actually youtube is not blocked, the anti-secular president tayyip erdogan’s videos are blocked. we can find many videos of him that contains lectures and reports which are against ataturk regime and ideology. (he has videos sitting-talking next to taliban) government used existence of anti-ataturk videos as an excuse, and blocked president’s videos indirectly as blocking we his anti-secular talks and ideas. that’s the real case.
its trap of Turkey.sorry about that
its lie its not true
so we can watch video on youtube. thanks for every think.
-im Muslim and im from Turkey.. i cant tell a lie .
Dear Selim what you said contradict what you wrote. You are muslim but you are agianst Mr. Erdogan. Howcome. The truth is, you and those people of your ideology do not want the real reason to come out; Peolple like you believe in dictatorship. Mr . Kemal was a dictator. as people express their view about Mr Mustafa Kemal, The army and elit group are bothered somehow. Because the reality means right of expressing right of diffending and seening reality of Mr, Mustafa Kemal.
The reality is slovely and nicely coming out. We are patient. People of turkey are patient too.
actually youtube is not blocked, the anti-secular president tayyip erdogan’s videos are blocked. we can find many videos of him that contains lectures and reports which are against ataturk regime and ideology. (he has videos sitting-talking next to taliban) government used existence of anti-ataturk videos as an excuse, and blocked president’s videos indirectly as blocking we his anti-secular talks and ideas. thats the real case.