I should clarify: Is the ‘site’ any good is a bit limited; it should be; ‘are the end results’ any good, as ideally we’d see an API and other useful re-usable systems/content come out of this.

Personally, I think that ‘API usage’ is an amazingly simple way of measuring the success of a project: if it’s useful, people will use the API (look at Twitter, eBay, etc.).