Ah, you guessed my next paper :) I have done a little informal analysis on the top 10 results from linked_lists vs the top 10 for that tag used as a Google query. They are quite different, almost totally different actually. But this is not really surprising if you think of the developers curating the links posted on Stack Overflow. I know there was an attempt a few years back to build a search engine based on the SO data set, don't know what happened to that.