The CAA expanded over the last few years to 12 teams (12 teams as of 2006 or 2007). Of those 12, 6 play football. NE, Hofstra, Delaware, Towson, W&M, JMU.
Since that was about half of the A-10 football league, the CAA decided to essentially take over the A-10 football league and call it the CAA football league, starting in 2007.
They invited essentially all the non-CAA member schools who played FB in the A-10 football league to play football in the CAA football league, whicle they remained in their primary conference for othere sports. It looks like everyone accepted, since this is really almost a name change only, from a member perspective. So Maine, New Hampshire, U Mass, Rhode Island, Villanova, and Richmond (who previously played A-10 football, but whose primary conference is the A-10, Big East, or American East) give the CAA football conference 6 more teams for a total of 12.