Q+ hangouts is a series of online seminars on quantum information and quantum foundations that take place in Google+ hangouts
Dan Browne founded “quant-ph” circle aimed to discussing latest preprint news etc. Write him to join.
http://www.quantiki.org/ with http://www.quantiki.org/video_abstracts
Preprint archives & Questions and answers
http://www.scirate.com/ (currently down)
Group lists & directories
http://www.quantumoptics.net/ (Quantum Optics and Atom Optics links)
Non-specific or general scientific professional networks:
Please, feel free to add another sites and blogs you know!