Interesting article. Although, I'm pretty sure he's mistaken about Belize being the farthest South that still speaks English officially. Guyana's official language is English, and it's on the South American continent.
Salesforce has been getting hammered on their lack of true analytics since the last Dreamforce. They have positioned their new SF1 dashboards as analytics, but anybody who knows better, knows that these are not analytics tools but visualization tools.
I'm guessing RelateIQ was a way for them to calm the industry influencers down, and give them a head start in plugging a significant hole they have had when being compared to the legacy stack vendors.
Competition already exists. Almost every major enterprise software company minus Oracle. Microsoft does have Yammer, but IBM has Connections, Salesforce has Chatter, TIBCO has Tibbr. There is an independent, Jive. There are also upstarts like Slack.
Facebook would be entering a market that is already crowded. I'm not saying they couldn't make a big splash, only that it's not monopolized by Yammer.
If you give credence to IDC, IBM is actually the market share leader, with Jive in the second position and Microsoft in 3rd.