In some ways MSNBC, which until 2005 was partly owned by Microsoft, is where Fox was a decade ago — in the early stages of profiting from its popularity. The channel receives a per-subscriber fee of 30 cents a month from cable operators; CNN receives twice that, and Fox News at least three times as much.

“When Microsoft was involved with MSNBC, it was viewed as kind of lacking in direction; I don’t think the channel had much leverage raising rates,” said Derek Baine, a senior analyst for SNL Kagan. “Maybe they will have some more leverage on this postelection.”

If Fox sees itself as the voice of the opposition to the president, MSNBC sees itself as the voice of Mr. Obama’s America. Its story resembles that of so many other cable channels. It hit on a winning strategy (antiwar liberalism led by Keith Olbermann at 8 p.m.), added similar shows (like Ms. Maddow’s at 9 p.m., which became the channel’s tent pole when Mr. Olbermann left in 2011) and then sold its audience as something more: a community of passionate, like-minded people.

Many progressives (and conservatives) now view the channel as a megaphone for liberal politicians, ideas and attacks against those who disagree. Such a megaphone — clearly marked, always on — has never existed before on television.

It has all happened rather suddenly. During the presidential election in 2008, Ms. Maddow was so new that she was still getting lost in the labyrinth of Rockefeller Center. And MSNBC was so timid about applying a political point of view that it paired an NBC News anchor, David Gregory, with the outspoken Mr. Olbermann on election night. The awkward pairing symbolized the split in American journalism between those who embodied a political point of view and those who said they did not.

Tensions between MSNBC and NBC News, which sit on opposite sides of that divide, have faded somewhat since 2008. They have stayed in their own lanes, save for a few reporters — Chuck Todd, Andrea Mitchell, Willie Geist — who have successfully crossed back and forth.