You may have missed the following 'editing comment' as it was inserted (anonymously) into an existing post and did not refresh the thread.

Hi kat, I think it may be a cultural thing because recently I've known people to post a blank message to say that they have seen the thread but they refuse to comment on it. Ther could also be other personal reasons.

A blank message doesn't take up much space on modern systems so I don't see why the clones just can't let them be.