Many of us actively use sites like Twitter and Facebook to promote our businesses. And those of us looking to connect with more business-related contacts may turn to sites like LinkedIn to develop relationships with people we have worked with or may want to work with.
With the growing use of social networking by business professionals, there is a growing number of social networking sites focused on business users and meeting their needs. Here is a list of 20 social networking sites for entrepreneurs, business owners and professionals that are worth a look.
Biznik – A community of entrepreneurs and small businesses dedicated to helping each other succeed.
biznik – A business website for UK entrepreneurs to get quotes, advice and more.

Cofoundr – A community for entrepreneurs, programmers, designers, investors, and other individuals involved with starting new ventures.
E.Factor – An online community and virtual marketplace designed for entrepreneurs, by entrepreneurs.
Ecademy –A business network for creating contacts and sharing knowledge.
Entrepreneur Connect – A community by where professionals can network, communicate, and collaborate with others.

entrepreneur connect
Fast Pitch – A business network where professionals can market their business and make connections.
fast pitch
Focus – A community focused on helping business decision makers and IT professionals make decisions.
JASEzone – A professional community where you can find potential clients and business partners.
LinkedIn – A professional network that allows you to be introduced to and collaborate with other professionals.

Networking for Professionals – A business network that combines online business networking and real-life events.
PartnerUp – A community connecting small business owners and entrepreneurs.
PerfectBusiness – A network of entrepreneurs, investors and business experts that encourages entrepreneurship and mutual success.
Plaxo – An enhanced address book tool for networking and staying in contact.

Ryze – A business networking community that allows users to organize themselves by interests, location, and current and past employers.
StartupNation – A community focused on the exchange of ideas between entrepreneurs and aspiring business owners.
Upspring – A social networking site for promotion and social networking.

XING – A European business network with more than 7 million members.
Young Entrepreneur – A forum-based site for entrepreneurs and small business owners who are passionate about promoting business for themselves and others.
Ziggs – A professional connection portal founded on the principles of professionalism and respect.
Do you have any other social networking sites for business that you use? Which one has worked the best for your business?

Details taken from  -