Look at page 1 and 2. There's one guy posting a dot, and the same guy posting a "lol" which is completely irrelevant to the topic. Then again, look at his post count.
The user in question is a regular user here, he apparently used to do that as a way of subscribing to the thread. If he was still doing it we'd talk to him about it but those are very old posts, not really worth removing at this point imo.