Does rel=”canonical” make it safe to use tracking parameters?

Matt's answer:
CUTTS: Here is a perfect question from Nick in Chicago “Does the new canonicalization tag make it safe to add tracking arguments to some of my internal links without fear that Google will split the quality signals between the two addresses?” So I believe you can do this. I would try it out on just one directory or small set of URLs at first, to make sure that it is completely safe. If you can fix it upstream, like if you can do something with cookies or your analytic’s package, where you can say, you know, I’m getting to this point of my page, so I’ll, I’ll track that event. If there’s a way to do it that way, that’s just a little bit better because, then there’s no, you know, suppose one copies and pastes a URL and they might copy and paste it differently and maybe that URL goes away or the tracking code changes. So if you can make the URLs unified, that’s still better, but I believe that this sort of thing can still work totally fine with the new canonicalization tag. Again, just start out cautiously, make sure that it works for you, make sure that there’s no problems, but this is the sort of thing that you can do, two conceptually same changes, maybe one is, I came in from the one front page, one was I came in from the help pages. You have a slightly different breadcrumb parameter or something like that. You can use the canonicalization tag to say really these are the same page and the same page is without this breadcrumb parameter, for example.
by Matt Cutts - Google's Head of Search Quality Team