Detect When User Reads Full Article? [closed]

Haven’t seen a plugin that does this, since each theme would differ. But for a custom solution that would work with Google Analytics events see #9 here: https://searchenginewatch.com/sew/how-to/2287906/10-google-analytics-custom-events-that-track-the-untrackable

OP also found this more specific article: http://cutroni.com/blog/2014/02/12/advanced-content-tracking-with-universal-analytics/

(These are in comments above, just posted to make it faster for those looking for something similar to find an accepted answer.)