With so many handsets to choose from, it's tough choosing an Android phone these days (unlike choosing an iPhone with only a few options available). So Google's stepping in with a tool to help you find the phone that most closely matches your needs.
The Which Phone tool asks you questions about how you want to use your phone--for taking photos, listening to music, gaming, messaging, and more. Each category asks at least one more detailed question (e.g., how many photos you take each week or what kind of games you play on your phone) before filtering the many potential phones down to a few selections. It also asks which wireless carrier you use, to make a better match.
In the resulting list of phones, you can filter by price range, screen size, and carrier and compare recommended phones side by side.
The tool is basically like walking into a wireless carrier's store and saying "I want to use my phone for this, this, and this, whaddya got?" Except you don't have to endure bad sales pitches and can do further research right away once you've narrowed down your options.