I predict that GitHub will acquire Campfire.
My bet was going to be Atlassian. They have the clearest competitor to Campfire (Hipchat), a history of pulling off acquisitions (Bitbucket) and from 37Signals perspective could probably make a better case that they could take care / migrate their customers.
We will not sell either of these products to a company that is planning to shut the products down.
IMO Hipchat is a better chat tool than Campfire.