OpenBC the social software application for professionals based in Hamburg, Germany has really earned a laudation. It only started in October 2003 and already features thousands of members. It is quite similar to other services like LinkedIn, but features a much stronger openness in general. Contacts can be made one-sided and most members can be contacted directly. A simple but very helpful plus is the obligatory photo which helps to recognize people strongly. Another big plus is the recommendation on the overview page for contacts of your contacts and new members. Even the rather disturbing "network" boards which work like news boards have frequent entries now. The best besides all these features is the "liquidity". Surprisingly many members that haven't found their way to LinkedIn have found their way to OpenBC. It's amazing how active many "social nodes" actively broaden their network.

Also, most services are still free. The premium membership is nice to have, but not really needed unless you are not working in sales. I'm pretty curious how the system will develop. The openness is often a blessing in the beginning and may result in a curse (spam& unrequested contacts) in the end. Maybe it turns out as a growth brake for OpenBC later on?