The Wall Street Journal has an eye-catching post this morning documenting Foursquare’s attempts to turn its 10 million users into revenue. The pioneer of the check-in has struck agreements with LivingSocial and AT&T to remarket daily discount offers, and it is in talks with Groupon to partner on a similar arrangement, according to the Journal. Delivering location-based offers to on-the-go users who willingly receive them (by checking in) makes a lot of sense, of course. But as my colleague Mathew Ingram points out, that’s a space that Facebook and Google are also rushing into — not to mention Yelp, Loopt and countless others. Foursquare is making the right moves, but it may discover that its big user base isn’t big enough.