[edited by: buckworks at 7:58 pm (utc) on July 3, 2009]
[edit reason] No URLs, please [/edit]
Given that domain names in the ccTLD realm are intended to reflect some connection with the host country I'll venture an educated guess that eventually ccTLDs will how a downside when attempting to present the website as a matter of global interest.
In other words, if you build a site about widgets on a .ca domain you may some day have a problem attempting to rank when marketing Australian widgets or widget services, which tend to be locally performed services (like home building, paving, etc.), to Aussies.
Search engine love is going to be perpetually finicky love, at best, so it's anybody's educated guess.
[edited by: Webwork at 2:16 pm (utc) on July 4, 2009]
Me if you do want to explore other markets get the .com if available or one really close to your nitch and have it become by main site and either 301 the .ca to it or keep the .ca active and build both sites.
Note if you keep both sites live be sure and keep them different in content so the duplicate issue won't get ya. If ya 301 the .ca to the new one you can just copy the whole site over and do a root 301.