I don't have any statistics to back this comment up but I think it's quite common these days for people to bookmark stuff to read later except few do and the list grows insanely larger by the day. This is base on what I've heard roughly from Marco Arment off handed once and I believe I've read the same or similar comment from one of the competitors to instapaper.

The issue then would be how much actually ever gets consumed and even if they do, how much "actual" learning takes place simply by following up on reading stuff. I'd argue most people bookmark stuff of interest, less so for real educational value which in of itself is subjective at this point