Now we know why Glenn Beck hates Van Jones so much: Fox News' ad revenue from Beck's show has been cut in half since Color of Change launched an advertiser boycott against the show.

Color of Change, the advocacy organization co-founded by Glenn Beck's archnemesis Jones, began calling on advertisers to pull their ads from Beck's show in early August, shortly after Beck accused Obama of having a "deep-seated hatred for white people." Since then, 62 advertisers—from Geico to Proctor & Gamble to Men's Wearhouse—have pulled their ads from his show even as his ratings surged.

Fox's stock response to the boycott has been that, while some advertisers may have moved their spots to other shows on the network, no one was pulling ads from Fox outright, so the whole hubbub wasn't affecting the network's revenues. But today, citing "data analyzed from industry sources," Color of Change announced in a release that Beck's weekly ad revenue dropped from $1,060,000 in the first week of August, when the boycott began, to $492,000 in the first week of September. The chart above shows the drop.

Color of Change's release doesn't say where it got that data, but we've been told the source and shown the raw data on the condition that we don't reveal where it came from: a well-known firm that tracks advertising revenue and sells its proprietary data. The firm monitors advertising on shows and uses rate-cards, ratings information, and its own industry contacts to estimate how much advertisers paid for each spot. While the firm sometimes performs analysis for the media, it generally doesn't like its proprietary information becoming public, which is why Color of Change won't let anyone say where it came from. While the numbers are only estimates and can't really account for the sorts of deals networks make with advertisers all the time, the firm is respected and regularly used as a best-guess estimate of ad revenue.

The chart puts the lie to Fox's claim about ads just shifting around the network—that may be true, but salesmen sell shows, and at some point the dearth of people who are willing to use Beck's paranoid sideshow to promote their brands has to affect pricing. And as we've shown before, he's been pretty much reduced to shilling for penis-enlargers and miracle egg-cookers. We've asked Fox for comment, but they haven't responded and almost certainly won't. UPDATE: They did! Kind of—a Fox spokeswoman directed us to the response they offered to TVNewser: "The Color of Change figures are wildly inaccurate on all fronts — revenue has not been affected in any way."

The irony here is that the revenue plunge comes during a month when Beck's ratings were off the charts, and Fox couldn't even capitalize on it. And in Beck's defense, the biggest week-to-week drop—from nearly $900,000 during the week ending August 16 to to just over $500,000 during the week ending August 23—came when he was off the air.