As for content that breaks the law, there isn't much of that in the U.S., for obvious reasons. Elsewhere it's another story.

As to politics, I don't think you can expect any of these sites to be politically neutral. YouTube, Facebook, Twitter, Reddit -- all show their bias. It's OK, it's part of life in a free market. There is a concern that many voices can be shut out of the market, and so maybe there will, at some point, be a decent rationale for temporary (say, ten years) regulations on digital town squares.