Finally GRRM has his own personal Twitter account (the ones you've seen before were all parody accounts). @GRRMspeaking is the man himself, and fittingly, his first tweet was a plug for his LiveJournal, which still exist, surprisingly.
If you donate $20,000 to his Wild Wolf Sanctuary and Food Depot campaign, George RR Martin will write you into the Song of Ice and Fire series (and probably kill you off). There are plenty of other more reasonable rewards, too. Any donation you make will enter you into a drawing to spend the day with the author, touring the wolf sanctuary. Check it out here!