Like pretty much everyone else who's a serious Internet user, I was eager to try Google Chrome. For once I was glad I still have a Windows install! So I downloaded it to my Vista partition, and gave it a spin.
It's pretty clear to me why Google have created this: Google want people to use the Internet more and more, because this strengthens them. The more efficient your browser, the more useful web apps such as Google Docs and GMail are. By raising the bar, Google are not only creating a great product, they're forcing other browsers to compete with them, even Internet Explorer. If IE doesn't step up to the challenge, they risk losing market share. If they do, then they're facilitating Microsoft's loss of market share for applications such as Word, Excel etc to web-based alternatives.
It's a hell of a strategy, and a classic Google one at that - Google don't compete, they change the rules of the game. They need browsers to get faster and more efficient to make them a match for Microsoft, so they've created Chrome to give them a platform for this. The fact that it's open source means that Apple, Mozilla, whoever, can pick out bits from Chrome to improve their own products, but also gives them a motivation to better it. Each browser that improves its performance like this means Google can compete more effectively with Microsoft.
Put it this way - I've heard that the reason IE spent so long without a new version being released (2001-2006) was because Microsoft were worried about the threat to their business model from the Internet. Now Google are aggressively pushing a new, faster browser that will change the game. I'm inclined to think Microsoft should be very worried.