Podio

The online-based Podio straddles two lines, online project management and business social network, with alacrity. It's one of the most comprehensive tools for small business communication and work management you'll find.

via PCMag.com Software Product Guide http://www.pcmag.com/article2/0,2817,2423451,00.asp?kc=PCRSS05079TX1K0000993