"The company says it is used by over 200,000 companies worldwide, and that 80 percent of the Fortune 500 firms avail its services.Yammer has raised $142 million in venture funding, with investors such as DFJ Growth, Charles River Ventures, Founders Fund and U.S. Venture Partners, as well as Max Levchin, co-founder of PayPal Inc." . . . . . . .