As explained by PMI.ORG, before your organization settles on one of the many collaboration tools available, be sure to:

• Consider what relationship you’re facilitating. Is it between employees who work in the same office or time zone—or on opposite sides of the world?
• Look for communication bottlenecks. Where can improvements be made and how can a collaboration tool support that?
• Define what function the tools will serve. Is it to facilitate project management, brainstorming or scheduling?
• Decide on your sophistication (and cost) needs. Will a free version suffice or do you need a more powerful tool?

Read the full article at: http://www.pmi.org/Pages/Tools-for-Teamwork.aspx