It would be very easy for link aggregators and search engines categorize sites as ad-supported or not: load the page in a browser (which these sites often alrea

It would be very easy for link aggregators and search engines categorize sites as ad-supported or not: load the page in a browser (which these sites often already do) with an ad blocker extension and see if it identifies anything. But my guess is they're not interested in doing this, since it rules out a lot of valuable pages. For example, HN is ad-supported.