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Dozens of Stanford grads walk out on Google CEO's speech
(www.bbc.com)
This is a most excellent place for technology news and articles.
On wiki it says there are about 1700 undergrads per class, so if it's that plus some grad students at graduation, 200 walking out could be maybe a tenth of the attendees. Sounds pretty noticeable.
Very rare for the ceremony to be the entire graduating class. Its usually broken down by school.