On my personal websites, I set up a comment system where anyone could comment by email because I thought it was funny and it was trivial to implement. As such, all my blog pages have mail-to links of the form comments+<blog-id>@site.
I have started to get spam emails from a few blog entries but whoever wrote the bot scraping websites fucked it up so it is instead emailing <blog-id>@site instead of comments+<blog-id>@site or comments@site.
I guess I should probably add something that goes between the + and the id so that I can automatically filter out those spam messages