On July 22, 2010, Google announced it would ramp up the speed at which it releases new stable versions; the release cycles were shortened from quarterly to six weeks for major Stable updates.  Beta channel releases now come roughly at the same rate as Stable releases, though approximately one month in advance, while Dev channel releases appear roughly once or twice weekly, allowing time for basic release-critical testing.  This faster release cycle also brought a fourth channel: the "Canary" channel, updated daily from a build produced at 09:00 UTC from the most stable of the last 40 revisions.  The name refers to the practice of using canaries in coal mines, so if a change "kills" Chrome Canary, it will be blocked from migrating down to the Developer channel, at least until fixed in a subsequent Canary build.  Canary is "the most bleeding-edge official version of Chrome and somewhat of a mix between Chrome dev and the Chromium snapshot builds". Canary releases run side-by-side with any other channel; it is not linked to the other Google Chrome installation and can therefore run different synchronization profiles, themes, and browser preferences. This ensures that fallback functionality remains even when some Canary update may contain release-breaking bugs.  It does not natively include the option to be the default browser, although on Windows and OS X it can be set through System Preferences. Canary was Windows-only at first; an OS X version was released on May 3, 2011. 
Note: Installing Google Chrome will add the Google repository so your system will automatically keep Google Chrome up to date. If you don’t want Google's repository, do “sudo touch /etc/default/google-chrome” before installing the package.