Greg Linden points out today that Amazon.com has redesigned its A9.com search page.

It now appears to be a metasearch engine, like Dogpile or Metacrawler, that gives a lot of control over which seach engines are used.

Greg says he likes the improvements, but I found myself a little confused at the categories. What is the "Web Booster" option? The engine also gives you the choice of searching books by Amazon, all of Amazon and then eight additional categories under the Amazon tab.

Here's Amazon's breakdown of the changes.