http://briancray.com/posts/estimated-reading-time-web-design
Interesting how a little detail can have such a big effect. An example of how setting expectations can have a big benefit.
Showing an estimated time improved time on site by 13.8%. What's more interesting though—people either followed me, subscribed to my blog, or retweeted my articles 66.7% more often.
Via http://labnotes.org/weekend-reading-500-feet-in-the-air/