India, Sept. 11 -- What happened when you complete college? You pick up your degree, smile in your best clothes at the convocation ceremony and head out of the gates forever - taking with you knowledge and invaluable memories. Do those gates open for you again? As an alumnus or former student, they swing wide, inviting you to share your experiences of the world outside with new students who've taken your place.

In most elite institutions, the power of the alumni association is undeniable. Colleges work to keep in touch with former students, and the students themselves form strong networks, drawing on campus relationships to leverage power and build trust particularly among MBAs and engineers. Now, other colleges are investing in harnessi...