Two different, and I mean major different frequencies and encoding. You must keep them separate.
i'm doing a little rearranging at my house. currently my comcast cable internet line is seperate from my dish network cable line coming into the house. because of rearranging, i was going to hook both signals through one cable line and split it to my television and the other to my cable modem in the same room.
will this be a problem having the two signals over the one line? anyone doing this currently? what kind of results do you have?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic