The TV talker Glenn Beck has spots of real popularity in the Northwest. The attention he has gotten is massively outsized compared to his actual audience (on Fox, about two million, or about two-thirds of one percent of the American population - not even a major sliver). But it has been enough to move book sales and generate substantial public appearances, like the highly-publicized recent events in Seattle and Mount Vernon, and in July at Idaho Falls. To judge from appearances and general public comments, he has a particular base of support in eastern Idaho.
That may have demographic reasons. Beck is a Mormon, since 1999 a member of the Church of Jesus Christ of Latter-Day Saints, and that part of the country is heavily Mormon. The situation is a lot more complex than simply pointing to the co-religionist factor; to suggest that Beckism is the same as, as matches cleanly with, all of mainstream Mormon belief and culture, isn't right. But if Beck's visibility continues to grow, exactly that may happen.
The first article (I've seen) addressing this squarely is a piece in the Boston Phoenix, "Latterday Taint," pointing out how Beck's approach grows out of a line of thought within that church, but just one one. The article is well worth reading. The LDS Church isn't entirely monolithic, and there are (relatively) liberal, mainstream, conservative and farther out elements. Beck's rants grow out of some of the more extreme and paranoid activism.
A lot of Mormons have cause to be concerned that Beck's fame has a backwash - that, in the minds of many, it comes to define them as well.