I'm honestly a little stunned he did it so soon.
I think the dems here need to be realistic about the possible risks to Obama from this position, however, he wouldn't have made such a move unless the risks had been considered.
I was a little worried about the potential downsides, too - doesn't really matter if he supports gay marriage if it loses him re-election and Mitt Romney passes a constitutional amendment to ban it federally - but polls show large majorities thought Obama backed it
anyway, so I'm hopeful it won't have much negative impact politically.