And how would you handle personalization without an account?
We usually advise startups never to make people create accounts if they can avoid it. Let new visitors do as much as they can without registering, but give them the option of creating an account if they want to save whatever state they've accumulated.
But in any case, I don't see how this product is better than Google News, for example.
most people don't know what cookies are.
Don't show me the flip button unless I can use it.
Also, I didn't know the buttom was a kill switch. I thought it was a vote IN FAVOR of the search result, like a Digg or something.