auto-tag

An  auto-tag  function is code that detects plain text tags (typically hashtags) and automatically marks up them with microformats tagging markup as a  in one's notes, photos, and reply posts.

Why
Writing plain text (typically inline in content) hashtags are much more popular than any formal tagging / categorizing system, thus it makes sense to provide a function that detects plain text hashtags and formally marks them up for at a minimum consumption by parsers explicitly looking for tags/categories, and possibly even auto-linking them to hashtag aggregation pages.

Tantek
undefined has an experimental "auto_tag" function he uses to convert
 * #hashtag to

Open Source
None yet.

Double underscore in hashtag for space
undefined has a need for putting spaces in tags for POSSEing to sites that support that, but wants to keep using hashtags (which disallow spaces) for tagging. So he's thinking of automatically turning double underscore (__) in hashtags into space in the p-category markup.
 * More info: Falcon