We were following Rypple for a long time, giving human ressource management a new vision. Now integrated with Salesforce, it's a great move, both for talent management area than for Salesforce (and Ryplpe :)).
It's clear that salesforce is building a strong social and collaborative ecosystem, with do.com, rypple.com, sites.com and of course after the success of chatter, they are little by little entering the space as a major palyer.