A couple of Yammer's top competitors are formerly VC-backed Salesforce.com's (NYSE: CRM) Chatter and Jive Software (NYSE: JIVE). Yammer has netted tens of millions more in venture funding than both of them, thanks to its latest massive round. Before going public last December, Jive landed a total of $97 million in venture financing from Kleiner Perkins Caufield & Byers and Sequoia Capital. The social business software provider raised $161 million in its IPO at a valuation of nearly $900 million. Cloud computing and CRM specialist Salesforce secured a combined $53 million from investors including New Enterprise Associates, Emergence Capital Partners, Meritech and more before going public on the NYSE back in 2004, raising $110 million in its IPO at a valuation of over $1.7 billion.