I first heard about Blekko through HN. I first learned of their API which I used to build most of unscatter.com on through HN too. The 3 card monte the original poster of this thread referred to, once again heard about it on HN. HN has also had links to articles about Blekko's investments from Yandex.

These were all front page. Over all I think Blekko has done a great job of being relevant and covered on HN.

Actually, here's a simple example. 44 pages when you search for Blekko using HNSearch - http://www.hnsearch.com/search#request/all&q=blekko