For the last few weeks, we've had an A/B test in the Android app where we measure user engagement with the "read more" suggestions that we show at the bottom of each article. We display three suggestions for further reading, based on either (A) a plain full-text search query based on the title of the current article, or (B) a query using the "morelike" feature in CirrusSearch.

And the winner is... (perhaps not entirely surprisingly) "morelike"!  Users who saw suggestions based on "morelike" were over 20% more likely to click on one of the suggestions.

Here's a quick analysis and chart of the data from the last 10 days: