The United States Patent and Trademark Office has issued details of a recent patent application made by Amazon.com, which describes a method for persistently storing and serving event data. Essentially, this allows their search engine, A9, to store and remember personal search histories. The original application was made in 2003, but withheld from publication until the search engine’s launch and subsequent filing of an international patent application.

Amazon’s search technology certainly has promise — at least assuming that tailored results don’t restrict occasional access to information falling outside usual search patterns. With A9, they’ve shown they can beat Google in rolling out the technology; now, in filing first for a patent over it — while Google’s still remains in beta — they’ve shown that Google has some serious catching up to do.