Weird off topic forum postings

There have been a few odd off-topic forum comments, saying things like 'Want to network?' and 'Thanks for your efforts'. They don't have any connection to the post they are responding to, and they come from odd sounding gmail addresses. They don't have any spam links in them so far, but still, weird. Anyway if you see them pls just keep them unpublished, unless they look legit.