YouTube blocked and unblocked in Thailand · Global Voices
Preetam Rai

Visitors to popular video sharing site YouTube were re-directed to a government web site from Friday to Saturday noon.
2Bangkok has a post on the block
When attempting to reach the YouTube site from within Thailand, the user is redirected to MICT. MICT is the government agency responsible for censoring the internet in Thailand. The reasons and criteria for blocking are usually not made public. In the past, if the resulting controversy over a certain blocking is too great, the blocked site comes back online and the government denies it was ever blocked at all.
MICT stands for the Ministry of Communication and Technology.
Speculating on the possible reasons for the block, forum poster Jromerz writes
Looking around in youtube now (after getting in without typing those three letters in the URL) and its still got blocks up within the site. If you click on a member's profile then you get the mict page again, and some (or most?) clips don't seem viewable.
It must be all those cnn interview posts
Jromerz is referring to the the clips from a CNN interview that features ex-prime minister Thaksin.     Thaksin was ousted by the Thai military and the current military backed regime is not happy with Thaksin getting any form of media exposure.
The 2bangkok forum has more discussion on the block.
There is no official word yet from Thai government if the blocking was deliberate. Thai authorities are known to have blocked sites before without warning.Personal Thailand writes
Turkey blocked the website today but government had some reason for it. Thailand has been known for blocking websites with out warning or reason before.
YouTube was accessible later in the day on Saturday.