Using Related Posts by Zemanta has literally exploded my page views and reader retention. I'm getting over double the amount of daily hits now on my little blog, and it's amazing to see people accessing older posts that even I had forgotten about! Trust me she I say that this is an essential plugin for any site.
Additionally, I had a whole host of coding issues when installing the widget (my fault, using a custom theme!) and the support guys went so far above and beyond the call of duty to help me get them fixed, even offering to help fix my coding issues that weren't anything to do with their plugin! Honestly, so kind of them.
Download this plugin today and see for yourself! It really does deliver and It's easily the best of the bunch.