edit: found it
A federal judge in Los Angeles last week ruled (PDF) that a computer server's RAM, or random-access memory, is a tangible document that can be stored and must be turned over in a lawsuit.
http://www.zdnet.com.au/us-ruling-makes-server-ram-a-documen...
Perhaps in heavily regulated industries such as banking that might be different but search engines are not government regulated (for now).
There was at least one court case where a judge felt this was enough to say "you have the document, you must make a copy at my request". I don't remember the details of the case, and don't remember how it ended. I hope that sanity prevailed and the "thou can not be compelled to create a document" policy was reinterpreted in a more reasonable manner.