How does he create pages from incoming searches

I wonder how does this guy to create new posts or pages from incoming searches, that in fact also get automatically indexed and ranked by google.

http://safe.mn/qbOu

He first shows several real posts related to the search, then a search box and then something with related incoming searches to the same page, also he hides it under a clever "/blog" path. I don't know it is a smart 404 I think, that also creates trash but indexable content.

Thank in advanced for your help folks

bump, anyone does know how to do it?