This week's selection of videos shows you how social networking sites like Twitter, Foursquare, Facebook, YouTube and StumbleUpon can be used in business, marketing, social change and self improvement.

How To Use Social Networking Sites To Promote Your Band

How To Build Your Business With Social Media

How To Use Twitter To Effect Social Change

How To Find a Job Online

How To Use Social Media To Boost Your Brain Power

How To Create a Grassroots Movement Using Social-Networking Sites

How To Use Twitter

How To Unlock Your World With Foursquare

How To Get Traffic To Your Website With StumbleUpon