WordPress Plugin Request (or, Does this plugin exist?)

I’m looking for a plugin that, when I publish a new comment, WordPress will automatically notify site update services (i.e., those configured in WordPress’s Writing Settings). I would like to have my reader’s comments show up in Google Blog Search, IceRocket, etc., search results.

Does a plugin like this exist? I don’t know what to call it. I’ve done some searching but I might have overlooked it.