This particular move was sanctioned by the Turkish government, which comes one day after a court did order the suspension of a ban on Twitter. According to the telecoms authority (TIB) there, it claimed that it had taken an “administrative measure” against YouTube, although there are other conflicting reports on the ground that talks are currently being held.
I guess you can call it a partial ban at the moment, since some folks were able to gain access to YouTube in Turkey, while some others noticed that access to YouTube was blocked. Turkey Prime Minister Mr. Erdogan will be participating in important local elections later this Sunday, and he has accused the media of spreading misinformation on him, hence leading many to suggest that bans will fall upon YouTube and Facebook both.
China and Pakistan both are countries that have banned YouTube in the past, so Turkey might want to buddy up with them on this matter.