Image via CrunchBaseZemanta has had a good year. You'll notice more and more blogs using their free widget. I use it heavily for picture recommendations (not so much on this blog but elsewhere). I think it's also worth pointing out just how good their customer care team is - especially for a free product!
Their latest offering does two things;
Traditionally Zemanta has taken link recommendations from a small bank of databases (like wikipedia). They've added a large dose of "wildcard" URLs with the latest update; 6,000 new URLs that have been popular links.
Zemanta have also started to track clickthrough rates. This means two things; it means the links inserted by Zemanta may loose some of their SEO value (they're going through the redirect domain
r.zemanta.com) but secondly there's added value in having a popular title as Zemanta may notice how popular your post was.
The advantage in Zemanta seeing that you're a popular post? We can theorise that this is connected to the first announcement that they've added 6,000 popular URLs to their recommendation engine. Be popular and Zemanta could recommend you.
Combine this with the API they released a few weeks ago and Zemanta is shaping up nicely. Any concerns? Not sure how they're going to make money. Selling the service to professional bloggers doesn't seem like a large revenue model to me... I suspect ad links are more likely.