Markerly's javascript allows us to collect all text selection as well as text selected and shared. It's all aggregate data, not personally identifiable. You can read about how publishers are able to optimize their content using the copy and paste analytics on this post http://blog.markerly.com/
Over 30% of people select text while reading. Markerly.com gives publishers a dashboard of text selection and copy and paste trends. We are about to roll out heat maps that show text selection - it definitely tells a story and differs article to article.
Source: I'm CEO of Markerly and I look at this data everyday.