Based on Techcrunch's stats, it looks like Chrome is pulling users away from IE, instead of Firefox. As Michael Arrington points out:

"If they hadn’t switched away from IE after four years of Firefox being around, it seems odd that they would jump ship now."

- http://www.techcrunch.com/2008/09/04/google-analytics-now-tracks-chrome-our-share-623/

Of course, it's also possible that those IE users didn't like Firefox all that much, and were waiting for something better to come along. Or, maybe the Google name is enough to bring people over whereas Mozilla is not.

This is only the first week of Chrome's release, and TechCrunch's audience is likely not representative of internet users as a whole. It'll be interesting to see how things shake out. I'm optimistic about the possibilities a new, better browser paradigm brings. Not only because I admire the design intent behind it (which is illustrated (literally!) in the famous Google Chrome introduction comic), but because it will encourage all the other browser makers to re-look at the way they're doing things. Pushing boundaries and questioning assumptions is essential for progress. And we the users all benefit from that.