I have been playing on Foursquare recently since it went "global" last month.

For anyone who hasn't come across it, Foursquare is a relatively new service which brings together social networking and gaming.

It allows you to check-in at specific locations (a bit like Brightkite) and post tips and reviews (a bit like Yelp), but also has a points based system allowing you to compete with your friends. Points are given for multiple venues on a night out, adding new venue and all kinds of other combos. It also links to Twitter so that your Twitter followers can see your check-ins.

Mobile clients are a prerequisite for this type of thing and clients are available for the iPhone, Blackberry, Android and Palm Pre at the moment.

Until the global launch it was limited to certain big cities (not much use for those of us on the Wirral!), but it can now be used anywhere provided that you don't mind adding your own venues as you go along.

Although it is basically a game, Foursquare is very interesting for businesses as it lets them run special offers for first check ins at their venue or for the "Mayor" of the venue (the Mayor being the user who has checked in the most times at that place). For the time being at least I have the honour of being the Mayor of Tebay Services on the M6!

Businesses have apparently been running these offers informally for a while (see the business section of the Foursquare site for details), but Foursquare are formalising this so that the offers pop up on your iPhone when you check in at or near a participating bar.

The other big benefit for businesses is that the check-in promotes their venue to the friends of the Foursquare user.

Tips from your friends pop up when you check in at a venue they have previously commented on. I got one of these the other day checking in at The Quarter in Liverpool with an insider tip about nearby bars which really brought home how useful the service could be.

I read a good post on Three Geeks and a Law Blog just after Christmas about the business possiblities of Foursquare for law firms. Please read the whole post, but to summarise the conclusion was that Foursquare probably wasn't for B2B generally and that "Law firms would be even more adverse to displaying this sort of information.".

I have been thinking about this myself since I have been using Foursquare and I can't decide whether there could be some scope for imaginative law firms to get some Foursquare love or whether this is a total non-starter.

Clients are unlikely to want to check in at your office when they come for meetings. However, maybe a firm which promotes a series of regular seminars or networking events could run an offer for regular attendees (check in via Foursquare and get a branded coffee mug... could you get more exciting than that!)?

The flipside is that maybe (some) clients will want to check in at their solicitors. After all, they can always add your office to Foursquare if they want and check in on their own initiative. There are certainly some law firms listed in the US.

Maybe if Foursquare does take off in the UK this will become another social media channel which firms will want to monitor?

Whatever the answer, I do think that Foursquare is a really interesting development in linking social networking to bricks and mortar... and for now at least it is a great way for downtrodden associates to leapfrog the promotion ladder and become mayor of your own firm!

*Apologies to any RSS subscribers who have had this twice - my fault for messing up settings. Won't happen again*