Sounds like the main story is that they're redefining what a major version number means a la Chrome. Chrome's numbers are not in the same scale as FF and IE too, of course. Users can't tell the difference between Chrome 6 and 7 like one can distinguish FF 2 and 3, or IE 6 and 7. I wonder, though, if Google was just trying to catch IE in version number with Chrome and once it's at 10, they'll stop increasing it so rap…
I doubt that the Chromium authors are concerned about trying to catch IE by having a larger version number. Their development calendar ( https://sites.google.com/a/chromium.org/dev/developers/calen... ) looks as though they have a rigid two-month schedule per version number. I myself am already running version 11 (screenshot: http://jhn.me/4RYO ) via their nightly builds.
Now look back: the public stable release of Chrome 1 was on 11 December 2008. That's roughly 5 up per year. In another year it will be 15 and then 20. After a while it will start looking silly (like it did with MS Office) and I don't think the question is if they will stop with this aggressive version-numbering, but when.
They now have beaten IE to the release of version 9, they will beat Opera for version 11. I'm guessing once they have beaten all the other browsers they will stop and get back to point-releases like everyone else.
But not until they are ahead of the curve and say "Your browser only goes to 9 or 10? My browser goes to version 11!". In lack of better words: Pointless or not, I'm guessing they want their browser to be the one which goes to 11, Spinaltap style.
The number is all a mind-trick and you have to be a fool not to see the game being played here.