Brett Tabke, founder of WebmasterWorld, asked in a WebmasterWorld thread if Google is once again crawling and indexing new content discovered from referral logs? Let me quote his full question:
Google started indexing SERPS from our new site search engine. The question comes up, HOW are they getting those search links? These are full keyword searches as performed by users.
When someone searches Google/bing/yahoo/alltheweb and then comes to WebmasterWorld - we highlight the page with those kw's and we also print "try this search on webmasterworld" with a full keyword link to perform a search on our site search engine. So a raw http link is there on the screen, only when someone kicks out a referral from a search engine. How does that link get into GoogleBot?
The only way I can think of is if google is reading pages via the tool bar or via that google accelerator proxy? Or is this just a reconfirm that Google is crawling out of it's referral logs?
What is interesting is that just yesterday I noticed that thousands of rustysearch results are now in Google. I believe this is new and I will try to get them out but it is an interesting coincidence. More details on RustySearch over here.
In any event, I am not exactly sure what is going on. That is why we have forums to discuss it.
Forum discussion at WebmasterWorld.