Windows 7 Tip: 
If you are a Joost video regular user and want to see all those Videos on your PC, than you have to try Adobe Air App Joost Media Player. Joost Media Player is an Adobe Air application that gives users the ability to view Joost.com’s extensive library of television shows, music and movies. The player has over 400 television shows, a library of over 10,000 music videos and a large selection of film.
In the instillation you can enter your Twitter credentials and the player will auto-update your Twitter account too.
Download Joost Media Player here
Really nice application , worth to have in your pc , Thanks for sharing