When we released Google Chrome Canary for Windows last year to help get more feedback on crashes from the bravest Chrome users, we weren't sure how many people would tolerate using a completely untested build of Chrome. Since then, hundreds of thousands of Windows users have contributed to Chrome's development by using the Canary and sending us valuable feedback. Thanks!
The Mac version of Google Chrome Canary follows the same philosophy: it automatically updates more frequently than the Dev channel, and does not undergo any manual testing before each release. Because we expect it to be unstable and, at times, unusable, you can run it concurrently with a Dev, Beta, or Stable version of Google Chrome. Your Canary data remains separate, but if you set up Sync in each version of Chrome that you use, you can automatically continue using the same set of bookmarks, extensions, themes, and more.