It’s routine for Big Media moguls to give money to political parties and causes. Rarer for them to publicly back candidates. Rarer still for them to do it on the Internet. But on the eve of the Iowa caucuses, Rupert Murdoch stunned everyone inside and outside media in recent days by tweeting praise for GOP presidential hopeful Rick Santorum, who has been rising in the polls. “Good to see santorum surging in Iowa. Regardless of policies, all debates showed principles, consistency and humility like no other.” And then came this Murdoch endorsement Monday night: “Can’t resist this tweet, but all Iowans think about Rick Santorum. Only candidate with genuine big vision for country.” It was Murdoch’s first weekend of tweeting: he began on Saturday during a family vacation on St Barts in the Caribbean. He used his verified Twitter account @rupertmurdoch accompanied by a very unflattering photo of himself.

Rupert’s praise for Santorum is being seen as the equivalent of a fourth-down conversion for the ex-Fox News analyst and former U.S. Senator from Pennsylvania. But Murdoch’s tweets show that he likes a lot of political figures: Ron Paul (“Great oped in WSJ today on Ron Paul. Huge appeal of libertarian message.”), NYC Mayor Michael Bloomberg, even a Democrat (“Obama decision on terrorist detention very courageous – and dead right!”)

But most amusing is how Rupert is using Twitter to promote his own News Corp products: the opinion page of the Wall Street Journal, a “great” book from HarperCollins publishers, the history of the New York Post, the replacement show for Glenn Beck on Fox News (“Got to watch Foxnews at 5 EST. Liberal Bob Beckel and team great replacement for Beck and much more fun.”). And, of course, Fox Filmed Entertainment: “Saw Fox film Descendants. Thank God, one to be proud of. Star Geo Clooney deserves Oscar, maybe film too.” … “I  LOVE the film “we bought a zoo”, a great family movie. Very proud of fox team who made this great film.”

So how long before Murdoch’s Twitter addiction wanes? Maybe any minute. As Murdoch replied to one of his Twitter followers on Sunday: “…I’m getting killed for fooling around here and friends frightened what I may really say!”