I think that two different types of college tracking are being mixed up here - the article is about tracking applicants, not those to whom random, unsolicited emails were sent.
This type of tracking is not new. If you search for it, I think you'll find some articles from a few years back (maybe 5-10 years ago) about admissions committees considering if an applicant had logged onto their portal. In one case that I recall, it was a good college, but one that tippy top students might use as a "safety". The committee noted that a tippy top student had submitted their application, but never bothered to go onto the college portal to confirm all items were received, and had no other interaction with the school other than submitting the application.
The committee either rejected or waitlisted the student. Such stories serve as a good reminder to students to follow up on their applications, and if they are asked to log onto portals, send a brief update after January 1st (MIT comes to mind), etc., they should do it.
