Twitter is cable tv for me. I get some national news, a lot of stuff I don't like and a little that I do from about 100 sources. I don't think I'll mind ads.
1) I don't know of any source that likes exactly the same things as I do. Think venn diagrams.
2) It's very easy to skim over the things that aren't interesting. I usually see tweets through flipboard and it's like a magazine. I scan for interesting things, and skip most of it.
This is the only way I know how to get the variety I want. I've thought about writing a statistical classifier to filter out a lot of it. I should get off my ass and do that.