How does Last.fm decide the geographic location of a scrobble?

Where are geolocations on scrobbles? :)

@tburny. You're right: in the api there isn't a way of associating a particular scrobble with a geographic location. But lastfm must do this somehow in order to make the geo api work.

@snyde1: Thanks for pointing that out. The relevant section reads:
We keep track of the domains from which people visit Last.fm, but we cannot see a user’s zip code, post code, city or country unless the user chooses to explicitly provide this information to us.

However that is ambiguous. They say they keep track of "domains," which I suppose means ip addresses (or at least part of ip addresses). That information does not guarantee that lastfm knows a users zip code, etc. But they can with high confidence infer where the user is at the moment of scrobbling by geo-coding the domain.

Can I get a straight answer from last.fm: is lastfm geo-coding the domains of users and does that information make its way into the geo API? It's a direct and simple enough question.

Thanks for the response ben-xo. I'm just surprised by that because the numbers in the lastfm.geo city charts api are quite high, and I imagine that only a minority of users type in their home city. But I'll take your word for it.