There is someone who has buddy requested me twice and I have declined both times and all their posts on this site are trying to get people onto yahoo chat with them. I am not interested in that but can't figure out how to ignore them so they can't keep sending me requests.
Under 'personal message options' in your profile you should be able to add people to an ignore list. I just looked at mine, and found 3 I had added long ago. I left them there.
If you girls would out some of the more annoying serial harassers, then maybe we can give them a taste of their own medicine. I mean after declining, saying 'no thanks' or otherwise 'get lost' to a person and they keep harassing you, they are certainly doing it to others too, and we can shame them into stopping.