Google's Matt Cutts continues to post helpful videos at Google's Webmaster Central YouTube channel, in which he answers user questions. The latest question he tackles comes from a guy in Chicago who asks:
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?
Basically, Matt just wants you to be cautious and make sure it works for you to avoid any issues.
If the Canonicalization tag is something you're not familiar with, it's something that Google, Yahoo, and Microsoft announced jointly a while back in an effort to reduce duplicate content.
Matt has also elaborated on the tag in a longer video and slideshow:
Matt is frequently posting informative videos to YouTube, which can generally be found here. He is also posting longer ones with presentations from conferences on his blog. These are both good resources for webmasters to bookmark.