The article doesn't claim that Google sold students' data. As is par for the course with Google, any data that Google processes is used to build up a profile of

The article doesn't claim that Google sold students' data. As is par for the course with Google, any data that Google processes is used to build up a profile of the user and then used to target advertising towards that user. The data itself is never sold, and the advertiser has no knowledge of who their advertising was delivered to nor does the advertiser know, if the person clicks through on the ad, why the person was served up that ad. It may have been because of the contents of their email; it may be because of prior searches; it may be because at one point they visited a website which was related; or it could be because Google couldn't figure out what was best and just served up some random ad.