What the government does is not the problem. Your ISP is more likely to know everything you do on the web than the US Government. If anything comes up the ISP gives the government access to their not quite legal data.
They’re tracking you with advertising cookies etc. Some people don’t know there is an option in most browsers to tell the website you don’t want to be tracked. I have the
Ghostery Plugin, but hey enjoy being tracked if you don't use a blocking app.!
On the other end, they usually will need a reason to track you. Thus, their keywords searches: things like “Bomb, Jihad, Terrorism”, you know stuff us average people don’t talk about. I’m sure there are some harmless words that are “code” for some as well not that I have the list. But I’m sure you can brainstorm some of the likely ones.