1. First to market means more as a B2B. A user may be using several generic social networks, but really only needs one professional network that references their specific industry.
2. A targeted demographic CPM and CPC is worth far more to advertisers. Advertisers want to go as deep as you can take them. Ensure this through diligent testing of profile questions. One set for advertising requirements and another set for the community.
3. Business partners are easier to identify and secure with cross-marketing deals. Separate them by revenue or traffic. You need both. As a vertical B2B social network, there are many more opportunities to monetize.
4. Word-of-mouth becomes the base that you build on and from this base, super-users rise to the surface. The 90-10-1 rule is alive and well here. 90% of your members read, 10% comment and 1% create content. Do what yu can to find and support and reward the superstars that represent that 1%. Drive toward a 5% goal for content creaters.
5. Educate your users on how they will benefit from using your B2B SN is extremely important. Help them fine the value and they will help you create that value.