Playing with old pictures in iPhoto.

The Wilderness Downtown

FoursquareFoursquare now has more than 3 million users, if the site's public user registration numbers are correct.The 3 millionth member appears to be Brian S. from St. Louis, Missouri, who has yet to check in to any venues via the mobile-based social network.Foursquare's growth has been accelerating rapidly lately. The service hit 2.6 million users on August 2, up from 725,000 in March. The launch of Facebook Places, which many thought would bring about the startup's demise, instead resulted in the biggest day of signups ever, CEO Dennis Crowley recently revealed.Given that Foursquare appears to have a little more than 3.02 million users now, we can determine that it is growing by more than 15,500 users per day (a little less than the 18,000 per day Crowley told the LA Times last week), or nearly half a million users per month.Although already rapid, that rate may very well pick up now that Foursquare has taken over Times Square.[via TechCrunch]For more Mobile coverage:Follow Mashable Mobile on TwitterBecome a Fan on FacebookSubscribe to the Mobile channelDownload our free apps for iPhone and iPad

A group of "professional couch potatoes," as one researcher described them, has proven that even moderate exercise -- in this case walking at one's own pace for 40 minutes three times a week -- can enhance the connectivity of important brain circuits, combat declines in brain function associated with aging and increase performance on cognitive tasks.

Here are 10 websites that might give you the winning edge over your fantasy football competition: