There's some shades of politics in some of the songs, but I don't think the album is a sellout by any means. In fact, I've become fairly certain that sellout is just another word for "Help, they decided not to release the same old shit for the fourth time and I'm gonna WHINE about it as loud as I can!"
If you're not convinced this is a new direction for them, listen to Shadow of the Day and Hands Held High. Shadow of the Day especially is a totally new sound for them. But you're right, q-pa. What I've done is probably the closest sounding to their other stuff on the whole album. Kind of the wrong single to sell a new direction with.
But I can say I've listened to the whole thing and there wasn't a song I didn't like, which is fairly impressive considering I usually hate any music with vocals in it. But Linkin Park's vocals have quite a lot of intelligence to them.
EDIT: Surprisingly, only a couple songs on the album were really emo. I was quite amazed.