Judging from their success selling ads during the just-completed upfront market, the major television networks appeared to be returning to health -- robust health at that. (The upfront market is a period in May and June when the networks sell about 65 percent of their advertising time for the coming season beginning in September; the remainder is sold, generally at higher prices, after the season begins during the so-called scatter market.) Overall, the Big 4 networks, ABC, CBS, Fox, and NBC, and the upstart CW together raked in commitments from advertisers worth around $8.6 billion -- nearly 10 percent above last year. Published reports, citing sources close to the negotiations, said that CBS led the field with sales of about $2.65 billion, up from around $2.5 billion a year ago, followed by ABC with around $2.3 billion; Fox -- which broadcasts 15 hours of programming a week compared to 22 for the other major networks -- with $1.98 billion; NBC with $1.7 billion; and the CW with $400 million. Today's (Friday) New York Times suggested that one of the reasons for the successful increase in ad pricing is that, thanks to social networks that encourage viewers to discuss shows while they're being aired, fewer people are watching them on their DVRs and fast-forwarding through commercials.