I have a pantry moth problem at home. These little buggers have gotten into open packages of rice, pasta, chips, and other foods in the pantry. They are harmless, but really annoying and they lay eggs which turn into these gross little maggots which writh around and crawl around the ceiling. I cleaned out the pantry and thought I got them all, but it seems a new pantry moth comes flying out just when I thought they had gone away.
Similarly, there are certain annoying posters on the SO who seem stuck on certain topics, especially partisan political ones or right wing social agendas, i.e. illegal immigration, blacks, what horrible things Oblamba has done, etc. A few have been around a while, but others come and go, and just when you figure they are gone, they come back or another one comes out of the pantry to replace him. They are harmless, but annoying, like pantry moths. I guess this is what you get when you have a message board in one of the reddest states in the country.