kottke.org posts about Sol Sender
The Obama "O" designer Nov 24 2008
Well, the "O" was the identity for the Obama '08 campaign and the campaign is over. That doesn't mean that the mark will be forgotten; I think the memorabilia from this campaign will have a long shelf life and will stand as a visible symbol of pride for people who supported the candidate and for those who see it as a representation of a watershed moment for our country. As far as having another life, I can't say. Perhaps the 2012 campaign will hark back to it in some way.
Sender's web site has a bit more info on the development of the Obama brand.