There are congressional hearings and there are comedy shows, and the twain rarely meet.

So when a House panel on immigration combined them on purpose last week with testimony from Stephen Colbert (kohl-BEHR') and his "truthy" alter ego, debate broke out on the proper roles of the many celebrities — from Angelina Jolie to Bono to Elmo — who advocate in Washington.

In Colbert's appearance, there was profit to be made from the public, taxpayer-funded forum on one of the nation's weightiest issues, the plight of migrant workers. Immigrant advocates won national news coverage; Colbert helped generate material for his show; politicians scored live coverage of themselves during a brutal election year; and the media bagged a widely viewed story.

Witness Carol Swain, the law school professor who testified before Colbert, was ticked at being overshadowed by a fictional talk show host. But she scored, too. Before the hearing was over, Swain's Twitter and Facebook followings soared. People e-mailed her at Vanderbilt University Law School. A guy recognized her the next day in the grocery store.