Even the best tools won't make up for talent that knows how to use these tools efficiently. When a tool like that is introduced in a company it will be a major effort because the potential users need to be trained on how to use it. In addition to that they need to be convinced that it is a good idea to participate because these tools are only valuable if users are willing ot invest time and maintain them. How do you do that? Without a critical mass of users and active management support there is a good chance that this won't take off as expected.
All this doesn't mean that it won't be a good idea to use a tool like that BUT it means that you need to put some serious effort into thinking if your company is really ready to use a tool like that effectively.
Other questions worth pondering are
- How many social communication tools are users willing to maintain?
- How many of your employees are already on Facebook or similar sites?
- What information can users exchange (and how fast) with this tool that they can't with the current tools?
- How are your current tools e.g. SharePoint working for your teams?
- Do you need a mobile version of this tool so that all users (e.g. Sales Reps) can use this effectively?
