Digital Video Broadcasting Project is an industry organization that develops technologies for the digital TV.
The three most widely used DVB's transmission protocols are DVB-C, DVB-S and DVB-T. All of these digital platforms are widely used, although mostly in Europe.
DVB developes not just transmission protocols, but also interactive standards for digital TV set-top boxes, etc. Various other DVB's protocols include MHP (multimedia home platform, also dubbed as DVB-MHP), DVB-M (standard for measuring DVB-S/T/C transmissions, etc), DVB-H (an "upgrade" of DVB-T standard that would allow using terrestial network to deliver DVB-T digital stream to mobile devices), etc.
DVB's homepage is here.