He maybe trying to promote his own coin since he has to recover he's recent losses.
Somehow I don't think Richard Branson needs to resort to price manipulation via blog entries to compensate for market fluctuations or recent losses. With a net worth approaching $5 Billion...I'm guessing he's reached a point in his life where he says what he believes, regardless of financial implications...
As evidenced by the B-Team:
http://bteam.orghttp://www.forbes.com/profile/richard-branson/