I don’t think so.
While RingCentral is certainly a very interesting company, with $300m+ in revenues … it’s too downmarket.
Salesforce has made a series of material acquisitions that are more SMB-y … ExactTarget for $2.Xb for sure, and even SteelBrick recently is more “downmarket” than say Apttus. RelateIQ’s customers were smaller tech companies, for the most part.
But very small businesses is, I think, one step too far downmarket for Salesforce.