Google Chrome Canary Compilation allows to run alongside another version of Google Chrome browser, yes, Google now allows to run two builds of Chrome simultaneously. You can install Google Chrome (stable/beta/dev) and then install the Google Chrome build (Windows only for now) as well.
Google Chrome Canary Building will be installed in a different path for Google Chrome (stable/beta/dev). Both builds receive updates separately. Also, the Canary build is the same as the dev build. Both current Dev and Canary builds have the same version number 6.0.472.0
The Google Chrome Canary build will be installed in a separate directory, using different user profiles and alternate shortcuts and icons.