@moonman 1. Tags (as in how they're actually recognized) are sent as Atom "category". How (_if_) they're represented in the rendered HTML is dependent on software that generates it.
I don't think we should mess with the rendered notices except perhaps hide stuff (like with notice URLs in !Qvitter that are shown as their full representations instead).

2. Not using a regex at least: https://stackoverflow.com/posts/1732454/revisions

Maybe if you stated your intended purpose with this I could come up with good suggestions. But I'd say you make a plugin that stores alternate renderings of notices. And then leave the notice table alone, and we'll put an Event in the $notice->getRendered() function or something.