1) Actively promote: going "viral" leaves too much to chance. You shouldn't design anything to go viral. You should have a proper communications plan to promote your social network.2) Develop content: create a bank of exciting, relevant and business-oriented content, at least for the initial quarter or half year.3) Identify and develop ambassadors and champions: the key to success are some enthusiastic users who can sustain conversation for some time, build traffic and act as mentors to new joinees.4) Don't forget the technicals: usually communicators tend to shrug away the tech part - design, usability and scalability. God help you if you aren't involved in the decision to buy the product, the tech support investment required and all that. 5) Last, but probably the most important: identify the business objective and stick to it. Everything - the tool you choose, the support you need, the content you develop and the enthusiasts you charter should be aligned to this goal.