Demonstrated interest matters enormously at some schools and is completely irrelevant at others. Here is a clear breakdown.
Schools That Do NOT Consider Demonstrated Interest
All Ivy League schools (Harvard, Yale, Princeton, Columbia, Brown, Dartmouth, Cornell, UPenn) explicitly do not consider demonstrated interest — they receive far more qualified applicants than they can admit and have no need to use engagement as a tiebreaker. MIT, Stanford, Caltech similarly do not consider it. Large public flagships (UC Berkeley, UCLA, University of Michigan, UNC, etc.) receive too many applications to track individual engagement meaningfully.
Schools That DO Consider It
Smaller private colleges and mid-sized universities are most likely to track and value demonstrated interest. These schools have more yield pressure — they admit students they're less certain will enroll. Engagement tracking helps predict who is genuinely interested.
How to Check Any School
Find the school's Common Data Set, go to Section C7 ('Relative Importance of Academic and Nonacademic Factors'), and look at 'Level of applicant's interest.' If it's rated 'Very Important' or 'Important,' demonstrated interest matters significantly at that school.