The 2010-11 season is more than half over, so it’s time to check in to see what you people are watching (or avoiding like the plague). The news isn’t that great for the Big Four: From the Sept. 20 start of the season through Feb. 13, every net except the CW is down among adults 18-49, the most important demographic to advertisers. CBS is posting the biggest drop at 12 percent, followed by ABC (11 percent), Fox (8 percent) and NBC (4 percent). The CW, in comparison, is up 11 percent (though that’s not exactly the sand box that the teen-loving network likes to play in). If it’s any consolation, the collective adult 18-49 rating for all of TV — and we mean every last network — is down 2 percent versus a year ago, so its not just the broadcast nets that may be taking a hit...