In my case, it's basically harmless. Reading the comments on those sites can however be quite amusing. For example there's one comment about how XP isn't a book and should be removed.

Uhm... ok, I wouldn't mind if they didn't blatantly reupload stuff. Since some of those comments are already over 7 months old, I don't think those websites will be removing my chapters any time soon.

At least they still credit me as the author.