I am in a LinkedIn community and have built a good core group in which to network with. The only thing about LinkedIN is that it isn`t business owners exclusively. There are a lot of employees that do not necessarily think about business after hours. What it does provide is a individualized online network system that you invite members that you know and want to expand your network with. Each member will open up their network to you and vice versa.
I want to tell you that Start Up Nation has put me in contact with more people that are business minded and hungry to grow than LinkedIn. I use it as a tool but I prefer your site.
I agree with Hugo on his point. I am also LinkedIn but do not use it very often. I have found it valuable as a tool for international contacts but is relatively difficult to locate the contacts due to the "Degree of Separation" criteria in contacts. However, I use another resource more often as recently I was selected as a VIP member of two International Registries for Executives and Professionals and it is very easy to locate specific individual members by Company Position and Market Sector throughout the global marketplace.
I also want to wholeheartedly agree with Hugo on his comments about SUN and I believe this will be a very powerful mechanism in the global marketplace.
I`ve sent a few invitations on Linked In to some of you, so I hope you`ll want to join my Linked In network. My profile is at http://www.linkedin.com/pub/0/6bb/47
I am also a member of Ryze.com, another business connection network. It is a lot like Linked In, except there are groups you can join within Ryze. If you`d like to check it out, and possibly join my Ryze network, please send me an email at scott.917 "at" acmedatallc.com
My Ryze profile is http://www.ryze.com/go/AcmeData