Oh, but "they" most certainly can! The terms of agreement of this site and all other social media sites state or imply this, where they state that your IP is recorded.

There is a clear electronic path between this forum and you, that is readily accessible to anyone holding a warrant.

Moreover, given the personal nature of the posts here, if some "interested" party wanted to sniff one of us out, it would only take a bit of browsing/searching and half-decent powers of observation. No warrants. Add a data harvesting bot or two and you speed the whole thing up 100-fold.

It is at improbable anyone will figure any of us out, only because, and as long as, it is improbable someone should take an interest in one of us. But it is entirely possible.