Canonical URLs and domains to most SEOs are a common issue they run across. How each search engine handles the various patterns of URLs that seem or are duplicate to each other, may differ.

In a Bing Community thread, there is a comment from Brett Yount, a Program Manager at Bing Webmaster Center, on how Bing typically handles WWW vs non-WWW issues. By that I mean, if you both the http://example.com/ and http://www.example.com/ URLs return the same page, without redirection. Brett said:

Forum discussion at Bing Community.