Why is this important? Well, to start with, Canadian sites will rank higher on google.ca as Google sees them as more relevant to the searcher. And most Canadian searchers will be on google.ca as in most cases, you are automatically rerouted, even if you type google.com. (The exception is in some searches in the navigation bar on your browser – I find I usually get routed to google.com there.)
Since most of us are looking for ad revenue, and our advertisers are generally looking for a Canadian audience, this is a good thing – it means more Canadians going to Canadian sites, which is the most useful kind of traffic.
So when checking your search results to see how you rank, make sure you’re checking google.ca – but look at google.com as well (or other English sites, like google.co.nz, for that matter) to see if you rank there, too. It’s interesting to compare the results.
And don’t be surprised if Google pushes our searches even more locally in the future.