While I'm always happy to see Romney have a little misfortune, I'm not sure if this really means anything.
There were no delegates at stake in Missouri and Gingrich wasn't on the ballot. So what you had was a win where Romney was only facing a single conservative in a state where they truly hate Mormons. (Seriously, Missouri didn't repeal Governor Bogs 1839 Extermination order until recently.) So that doesn't impress me that much.
Minnesota kind of surprises me, because Romney won that won in 2008 and he had Pawlenty out shilling for him. Then again, I may have just answered my own question. BUt he came in THIRD place behind Ron Paul.
Colorado was the one that shocks me, because Romney had a lot of organization there, a sizeable lead.
Long term, I don't think it matters. I think we are now going to see the Mainstream Media launch into a bunch of attacks on Santorum, and Romney still has the money and organization to go the distance.