An advertising boycott against Fox News host Glenn Beck has succeeded in keeping most major sponsors from running commercials on his show even as the controversial commentator's viewership has grown.

Beck attracted 2.81 million viewers Monday, his third-largest audience since his show launched on Fox News in January, according to Nielsen Media Research data provided by the network. On Tuesday, nearly 2.7 million viewers tuned in, his fifth-largest viewership to date. And the conservative host got a plug from former vice presidential nominee Sarah Palin, who urged people to watch his program in a post on her Facebook page.

“FOX News' Glenn Beck is doing an extraordinary job this week walking America behind the scenes of 1600 Pennsylvania Avenue and outlining who is actually running the White House,” she wrote Wednesday to her 800,000-plus supporters.

Color of Change, an African American political advocacy group, organized the boycott last month to protest Beck’s comment that he believes President Obama is a racist. The group succeeded in securing commitments from at least 36 companies that have pledged not to advertise on his show, including Wal-Mart and Sprint. Some, such as AT&T and Procter & Gamble, were not Beck advertisers to begin with, but their ads had mistakenly appeared on the program. Representatives from those companies reiterated their request not to have spots during his show. Later today, Color of Change plans to announce six more companies that also are declining to be Beck advertisers.

As a result, few major businesses remain as sponsors of Beck’s eponymous 2 p.m. PDT program. On Wednesday, the only big companies with a presence during his show were Bank of America and the Wall Street Journal, whose parent company News Corp. also owns Fox News. The rest of the commercials included spots for gold seller Rosland Capital; Ashley Furniture Home Store; Empire Carpet; Liberty Medical, a diabetes medical supplier; Johnson Law Group, an asbestos litigation firm; “Shadow Government,” a new book critical of Obama published by the National Republican Trust; and the anti-tax group TeaPartyExpress.org.

Fox News insists that the boycott has not affected its revenue, because advertisers have just moved their commercials to different time periods. And for his part, Beck appears invigorated by the challenge. “Even if the powers to be right now succeed in making me poor, drum me out … I will only be stronger for it,” he said on the air Wednesday. “And I will use American ingenuity and my ingenuity to pull myself up, and I will find another way to get this message out, on a platform that will be a thousand times more powerful. Because of my faith, I know how this story ends. The truth will set you free.”

Since returning from a weeklong vacation Monday, Beck has not explicitly addressed the boycott. Instead, he has launched a weeklong series called “Reasonable Questions for an Unreasonable Time,” in which he has argued vehemently that the Obama administration is being infiltrated by radicals seeking to undermine the U.S. Constitution.

“I have demonstrated that these radicals are not only instrumental in shaping legislation that is being jammed through at light speed, they are also by invitation personally advising the president of the United States,” he said Wednesday, calling them “radical wolves that are about to devour our republic.”

One of his most frequent targets is Van Jones, special advisor for Green Jobs, Enterprise and Innovation at the White House Council on Environmental Quality. In 2005, Jones co-founded Color of Change with James Rucker, the group’s executive director. Beck supporters have charged that Color of Change launched the boycott of Beck's show in retaliation for the host's criticism of Jones.

Rucker said Jones has not been associated with the group for more than a year and had nothing to do with the boycott. "I didn’t even know Van had been a subject of Glenn Beck’s sustained attacks until after we had launched the campaign," he said. "I can say absolutely there was no involvement by Van or the White House. Beck has made these claims that are not fact-based and he needs to change the subject, and that’s what this is all about."

Beck began railing against Jones earlier this summer, dubbing him one of 32 “czars” with unchecked power in the Obama administration. He has repeatedly called him a communist, citing a 2005 profile of Jones in the East Bay Express that described Jones’ shift from a radical-activist past to more mainstream politics. On Wednesday, he made reference to the fact that Jones named his son after African guerrilla leader Amilcar Cabral.

“Should you have a communist, self-avowed revolutionary who named his 4-year-old son after a Marxist guerrilla leader, should that person be advising the president of the United States?” he asked.

Jones did not immediately respond to a request for comment made through the White House. Earlier in the week, White House spokeswoman Christine Glunz said in a statement that Jones has been lauded as an environmental hero and that his entire focus at the Council on Environmental Quality is on “building clean-energy incentives which create 21st century jobs.”

[Updated at 1:33 p.m.: According to Color of Change, 10 more companies that have recently had ads air during Beck's program have pledged not to run any further advertising on his show. The latest businesses to distance themselves from the Fox News host include Applebee's, Bank of America, Bell & Howell, DirecTV, General Mills, Kraft, Regions Financial Corp., SAM (Store and Move), Travelers Insurance and Vonage.

Bank of America, which had a spot on Beck's program Wednesday, pointed the group to a statement it gave Media Matters for America stating that its advertising had been placed on the program in error. Travelers Insurance, Bell & Howell, General Mills and DirectTV also told Color of Change that they had already placed Beck's program on their "do not air" lists and any commercials that appeared during his show were in error. Applebee's told the group that it was now dropping Beck's program, and Kraft said it had decided to stop advertising "on the more politically extreme programs on all networks."]

[Updated at 2:15 p.m .: According to a Fox News spokeswoman, the network has not run Bank of America ads during Beck's show, so any spot for the bank that aired during his program would have been a local cable purchase. In addition, the network said that Bell & Howell and SAM (Store and Move) were never Fox News advertisers.]

[Updated at 3 p.m.: SAM (Store and Move) is indeed a Fox News advertiser, a network spokeswoman clarifies. The company buys ads under the name Unigroup.]

[Updated at 4:43 p.m.: Beck posted his second-highest viewership ever Wednesday, attracting more than 3 million viewers for the hour.]

[Updated at 8:07 a.m., Aug. 28: Ashley Furniture HomeStore pulled its advertising from "Glenn Beck" as of Thursday, said Kendra Maggert, a spokeswoman for the company.]

-- Matea Gold

RELATED:

Glenn Beck goes after Color of Change co-founder Van Jones