[Shakattack]

After reading this, I was a little creeped out: http://www.guardian.co.uk/technology/2010/jul/23/foursquare

But my general policy with posting online content is if you put it online, don't be surprised when people find out. I think the ad agencies tracking 4sq check-ins is key to monetizing location based services, and I'm all for it because it just makes sense. When/if this happens, 4sq and others will hopefully be transparent about it, so users know what they're getting into.

But if you don't want people/companies to know where you shop, don't check in. Simple as that.