User:
    -address
    -email
    -title
    -business url

Tag:
    -count
    -tag string

TagAssociation: # basically a NoSQL join table of user<->tag
    -user_id
    -tag_id

Commit 66f2a599f7f6f25a2ddb68f1b6f25cbd277396d9 has just the User model with
authentication/sessions working with MongoDB. Anything after that has the User,
if he specifies a URL, get autotagged based on the categories associated with
his site on http://www.dmoz.org, the human-curated categorization site.

Future updates:

1) Make the user discoverable based on his tags, by leveraging ThriftDB for a 
simple, powerful search tool.

2) Auto-updating, navigational tag cloud for visual search.