As of Enterprise 2.0 is coined by Harvard Business School Professor Andrew McAfee, many organizations have been looking for sociable applications to indirectly improve business productivity. Twitter or Facebook or other well-known at that time might fall into their eyes. However, due to publicity, they actually could not fit. How about MOSS 2007 at that time? Well, people were looking at it as a platform which has social features preferably, but not many. Then, Yammer, which is one of the enterprise social networks was launched, attracting numerously organizations over the world with more than 80 percent of the Fortune 500.