Obama appeared on Meet The Press in October 2006, and indicated that he might be interested in running for president in 2008 after all, and that he'd decide within a few months. That made a big splash in the media, and he instantly jumped to 2nd place (after Clinton) in all the Democratic primary polls.
Today, Roemer indicates that he might run for president, and it gets essentially no coverage. Here's Google News on "Buddy Roemer":
http://news.google.com/news/search?aq=f&pz=1&cf=all&ned=us&hl=en&q=buddy+roemerPretty pathetic. I highly doubt that Roemer is going to be invited on Meet the Press any time soon. And no one is bothering to include him in any 2012 primary polls, and I doubt they're going to start doing so in the near future.