Foursquare launched last week, and it's been interesting to see how the social app has been taken up.  It's not just a social app, it's a game, and it's turning the whole of London into one, apparently.

Whilst it's been pointed out that users checking in to a tube station is as necessary as checking into a bus (to clarify, this is seen as going a little too far) the user reception seems to be pretty good.  The main point is to log where you are in the city, through a simple interface.  The game aspect is in the use of points given for going out every night of the week, reviewing or commenting on restaurants, clubs and bars, and for being the first to go to a new place.

Using the application you can update your location, keep to-do lists, and most importantly see how your points and achievements are doing.  Also a nifty part is the use of the 'checking in' function as a loyalty store card.  In July co-founder Dennis Crowley said that the company had seen growth of more than 20% each week.  Now, not confined to existing USA popularity or new English rising popularity, Foursquare has gathered $1.35 million of further funding and should be hitting new markets such as Paris soon.

Yes, not only is the Foursquare app filling up Twitter with lists of users' new achievements, badges and points, but it may unwittingly be causing a surge in social life.  Or they may be sitting at home, lying.  It's really quite versatile.

How do you feel about it - or if you haven't tried it, is it more than apathy that's put you off?  I'm quite content to leave this to new adaptors and see the outcome myself (not solely because of a lack of an iPhone).

Steve Rubel interviewed co-founder Dennis Crowley in July earlier this year: