And we find he almost worked for MSNBC:

I ask him with all the changes going on at CNN, which like HBO is owned by Time Warner, if he could take his brand of politically incorrect talk to the all news network. After all he’d often sit in for Larry King, when King was a CNN mainstay. “Never, going to happen,” says Maher. “A while back I had some extensive talks with MSNBC and ultimately we all looked around the room and we all just knew with advertisers to worry about, we’d never be able to make it work.”

If Maher toned down his HBO show for MSNBC, he’d be the highest-rated host at the network.