I believe TV is worse. While the Internet can be worse or as bad for some, it certainly isn't for all. Sure, I might have a lack of self-control on the Internet, but all that amounts to is spending too much time reading CathInfo when I should be attending to something else. That's not nearly as bad as being subjected to whatever the TV decides to throw at me.
Generally speaking, you have control over what you read / view on the Internet (even video ads on YouTube can still be skipped after a few seconds) while you have very little control over what you view on "live" TV.
I do use the internet to watch some TV programs, but the absence of advertising is a huge improvement even if the program itself is still getting its chance to paste it's point of view on my brain.