Previously, there was only three “channels” for the browser we know and love, Google Chrome — Stable, Beta, and Dev. Starting today, Mac OS X users will now have access to Canary (as Windows users have for quite a while), which is a different version of the regular Chrome browser, so that when updated you don’t have to remove preference files, and so forth. Think of Canary as a “pre-Dev” version of Chrome.
As the Google Chromium blog states:
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.
Oh, and the yellow icon looks awesome. Using it now, I might add.