The OpenSocial alliance among a variety of consumer social network sites (SNSs) — most notably MySpace — is designed to allow marketers to leverage as never before the word-of-mouth strength of a social graph. This story about the less-known business vertical SNSs (such as those catering to physicians and telecom professionals), reminds me of this exciting reality:

Any b-to-b site with an active community and the flexibility of adopting OpenSocial can reap the same benefits.

Below is Google’s somewhat dorky video explaining the OpenSocial API.

Also, here’s a terrific explanation of what a social graph is, why marketers should care, and what they should do with the sites they manage in light of this information.