display leaderboard to show the top taggers

[michaelkirk]

blah blah blah gamification...

Rank players by:

Number of correct guesses.
Number of spots created.

Ranking by score might encourage people not to spend their points.

Eventually this should be location specific. e.g. your ranking within a certain distance, or specified group, but for now, it will just be global (since so few people are playing).