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Well, they started out with the self-reported chosen college of the students – MIT has a line on the admitted student reply card for the student to write where they chose to enroll over MIT. The vast majority of admits were categorized in that way, not via Facebook. :)</p>
<p>Facebook was useful for that purpose for people who had relatively unique names. For people with common names, it was not useful – I think that probably all of the small number of people I couldn’t find were people with common first names and surnames.</p>