I'd like to answer that in detail but it's impractical to do so here as it'd take pages. As a starter though begin with them not violating users' privacy.

Another quick point: my observation is that the worse the ad problem the lower quality the content is. Cory Doctorow's "enshitification" encapsulates the problems in a nutshell.

If you have enough detail for a blog post I'd heartily encourage you to submit it.