http://www.collegemagazine.com/10-best-college-alumni-networks/
According to Time Magazine, Michigan’s alumni network is the 2nd most influential in the nation (tied with Columbia and second only to Harvard)!
Michigan’s alumni network is extremely gifted, intellectually brilliant, ridiculously large, very spread out, immensely diverse (in terms of career types), very wealthy, frightfully powerful and best of all…very loyal!
Columbia does indeed have a large alumni cohort, especially in Wikipedia and especially compared to Michigan (something on the order of 3,600 alums for Michigan versus something on the order of 4,600 for Columbia). That said, enough alums have been added to Wikipedia that were that Time widget to be rerun by the folks at Time in light of the new data in Wikipedia, Michigan would easily surpass Columbia not on the basis of headcount, but on the basis of “influence” as measured by Time.