Not sure what criteria they use, but here is the Nielsen ratings people's assessment based on 'number of TV homes' in 2010:
1 New York 7,493,530
2 Los Angeles 5,659,170
3 Chicago 3,501,010
4 Philadelphia 2,955,190
5 Dallas-Ft. Worth 2,544,410
6 San Francisco-Oak-San Jose 2,503,400
7 Boston 2,410,180
8 Atlanta 2,387,520
9 Washington, DC 2,335,040
10 Houston 2,123,460
Largest non-MLB market was 19th-ranked Orlando/Daytona/Melbourne at 1,455,620; Baltiless came in 27th at 1,093,170.
Orlando and Daytona are one media market? They're further apart than DC and Baltimore.
