1. Adoption - There is no doubt online communities are valuable and powerful, but there is no value if your community is an empty dance floor. Generic communities based on generic tools, often have no stated purpose and employees or customers don't know why they should go there. Idea Portals are a proven way to get very rapid uptake because there is something in it for the end user. Either participating in the product direction or cutting costs instead of headcount...there's an obvious 'What's in it for me?' and that drives rapid adoption out of the gate.
2. ROI - In today's environment the bean counters are holding the purse strings pretty tightly. So a technology looking for a problem is dead on arrival. However with Innovation we are often talking to our customers about Millions, Hundreds of Millions and Billions of dollars. By connecting the benefits of social networking with the innovation process the ROI is obvious, immediate, quantifiable and large.