this would be nice for catching when other people post a link to your post in a silo.

i did this for a while in mid 2012, before bridgy's re-release with webmentions. i stopped because the POSSEd posts showed up as comments on the original posts, and i kept that decision in the re-release because i didn't see enough people using rel-syndication links, which meant i couldn't prevent the same thing happening to them.

on the other hand, we've been thinking more about de-duping and similar issues recently, and @tantek proposed that this kind of noise might help motivate people to make their mention handling smarter. worth a thought.