Code organization wise, it looks like things are a bit spread out here.  I think it'd be preferable to keep all of the media embed stuff in one file as makes sense. Specifically:

* the parsing of updates and enqueuing of messages should be in this file (not models)
* the property that pulls embeds from the update object looks good where it is in models
* the twitter scraper etc. should be in this file, scraper.py is for hooking into core-reddit's scraper to provide liveupdate embeds (might be removable in the future if we get liveupdate hooked up in embedly)