It has a lot in common with tracking bills.
Only, you are tracking virtual items, that can be common or rare.
I just signed up, and seems like fun... but Europe is still very quiet (seems like the early days of eurobilltracking
)Android
https://play.google.com/store/apps/deta ... tion&hl=nl
Iphone
Appstore "Itography"
edit : you can sign up anonymous. But you can also use facebook and foursquare (optional)
The locations are foursquare locations, but you don't need to check in to used them