Sinclair Broadcasting is making the news because of their censoring of ABC's Nightline from their stations. Here's some background on Sinclair from an article from alternet from last year.
http://www.alternet.org/story.html?StoryID=15718Excerpt:
"The Rise of Sinclair Broadcasting
Like many a media empire, Sinclair grew through a combination of acquisitions, clever manipulations of Federal Communications Commission (FCC) rules, and considerable lobbying campaigns. Starting out as a single UHF station in Baltimore in 1971, the company started its frenzied expansion in 1991 when it began using "local marketing agreements" as a way to circumvent FCC rules that bar a company from controlling two stations in a single market. These "LMAs" allow Sinclair to buy one station outright and control another by acquiring not its license but its assets. Today, Sinclair touts itself as "the nation's largest commercial television broadcasting company not owned by a network." You've probably never heard of them because the 62 stations they run – garnering 24 percent of the national TV audience –fly the flags of the networks they broadcast: ABC, CBS, NBC, FOX, and the WB.
TV Barn's Mark Jeffries calls Sinclair the "Clear Channel of local news," a reference to the San Antonio, Texas, media giant that has grown from 40 to more than 1,200 stations today thanks to the 1996 Telecommunications Act, which relaxed radio ownership rules. But the parallels extend beyond their growth strategies. Jeffries describes Sinclair as having a "fiercely right-wing approach that makes Fox News Channel look like a model of objectivity," while Clear Channel is best known for sponsoring pro-war "Rallies for America" during the Iraq conflict. And like Clear Channel's CEO L. Lowry Mays – a major Republican donor and onetime business associate of George W. Bush – the Sinclair family, board, and executives ply the GOP with big money. Since 1997, they have donated well over $200,000 to Republican candidates."