I'm almost pretty sure that's just a spam post to promote an unrelated web site link in the footer.
Just in case: there's event plugin DBClean serendipity_event_dbclean that does a database cleanup of some entries that pile up quickly.
how to reduce database size
Re: how to reduce database size
Running s9y at https://erack.net/blog/
Re: how to reduce database size
I checked the site, it's being spammed around, so I think you were right. I banhammerd the account. Your answer was right though :)
Re: how to reduce database size
yes i am also agreed that he is right