There are lots of uses for this, but my main advice is to not loose these three things: 1. advantage of relevancy within specific domains. The page-rank was a

There are lots of uses for this, but my main advice is to not loose these three things: 1. advantage of relevancy within specific domains. The page-rank was a huge value-add to relevancy over other search. But internet wide is now too ambitious. HN is a great corpus because the content is already vetted by a community. The work of integrating other specialized communities content can give density and relevancy. 2. ease-of-use in integration. The less configuration to use this API, the better. Autotagging, done well, is very useful. I have a lot of ideas around this if you'd like to chat some time. 3. ease-of-use interface . Combining browsable, faceted search with NLP is, I think, the sweet spot between getting lots of relevant results, but allowing for discovery.