PBS is crediting improved video offerings and search engine optimization efforts for helping propel its traffic upward 25 percent over last year, a leap that helped it beat the broadcast nets’ sites. Citing Hitwise stats, during the weeks of May 31, June 7, 14 and 21, the public broadcaster’s site ranked number one in market share with numbers around 24 percent of U.S. visits among TV networks. It was followed by ABC.com (around 20 percent), with NBC.com, Fox TV sites and CBS (NYSE: CBS) fluctuating between 13- and 18 percent during the past few weeks.

But when it comes to metrics, it depends who you ask. Looking at the entire month of May, comScore (NSDQ: SCOR) ranks ABC.com highest for broadcast TV networks with 9.7 million uniques compared to PBS.org with 3.8 million uniques. The year-over-year leap for PBS wasn’t that great either, according to comScore figures: in May 2007, PBS attracted 3.6 million uniques for a gain of 5.6 percent.

-- Update: PBS rep Kevin Dando says the company’s internal numbers (monthly uniques: 10.2 million; visits: 13.7 million, according to Visual Sciences) correspond with the Hitwise data, especially the year
over year increase, and makes the oft-heard argument that comScore undercounts the site’s at-work users. He added that PBS values visits over uniques, not because the numbers are naturally higher, but because “it’s more indicative of habitual traffic.” As for comScore, it measured 5.1 million visits in May 2007 to PBS.org and 5.7 million, which gives the public broadcaster a year-over-year rise of 11.8 percent.

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