As you may have noticed from watching all the New Year's Day games, a plethora of tickets were still available at the bowl games, particularly the Gator Bowl.
For the Outback Bowl, the addition of Michigan did help increase attendance (54,527 vs 49,429) somewhat but it was still far from a sellout. In terms of TV, the rating dropped quite a bit, from a 5.0 (MSU/Georgia) to a 4.3 (UM/SC).
It's obvious Georgia is a bigger TV draw than SC, but I'm a little surprised Michigan didn't help keep that number closer for 2013. Pairing this with the poor showing of last year's Sugar Bowl (3rd lowest BCS game of all-time), it seems to confirm that while we're a big TV draw (compared to 95% of programs), we're not quite big enough by ourselves to draw a huge numbers of viewers.***
(Note on link: while the ratings are as solid as TV ratings get, take the attendance figures with a grain of salt; there is simply no way there were 70,000+ at the Orange Bowl -- on TV it looked like a typical U of Miami game.)
***Update: as 'Murph' pointed out below, the Outback bowl was on ABC last year, not ESPN. Since ESPN is in 87% of TV household (essentially 5/6), this means the "normalized" number for last year's Outback would be 4.2 -- thus the TV rating was essentially unchanged from 2012/2013..