Amazon has opened up a beta of their A9 “Google Killer” search engine. It’s pretty cool. Has several nice innovations in the UI and seems to be making use of some Alexa data as well. It’s still basically just a Web search engine, with more personalization, but well-executed, and may even provide a better search experience than Google presently offers. Personalized search — a search engine that remembers and learns from my previous searches (and those of my friends a la Eurekster) — is definitely a key way to improve search.