BTW, Nate Silver (yeah the political dude) posted a pretty interesting article a couple of years back.
Essentially his data shows that Ohio State, Michigan, and Penn State are the three most popular colleges in all of football (and are by a fairly wide margin). They are followed by Notre Dame, Texas, Texas A&M, Auburn, Alabama, Florida, and Clemson.
It is actually a pretty good read.
The chart I posted earlier in this thread is from this article. It clearly shows why Rutgers is coming to the Big Ten. Maryland on the otherhand, makes less sense from a popularity standpoint (it will be the least popular school in the big ten), but when you consider that the Big Ten has none of the markets where Maryland gets its fans, it makes a lot more sense as an add.