I never heard of this before I visited seobook.com. Is this a real issue for link juice? If so does that mean any time you refer either internally or externally to you site, you need to do all of this http://www.sitename.com?
It used to cause problems because of the way SEs treated hxxp://site.com and hxxp://www.site.com differently. SEs have improved. For peace of mind, use any one form consistently.
The other point of interest here is relative URLs. Relative URLs are treated properly by most search engines now for most purposes (I do not want to write a lengthy essay about the exceptions). So, you don't need to worry about that.
It's such a long weird word, that I'll bet most people misspell it. Thanks for the reply, it makes a great deal of sense. Only thing I am still not clear about is do you really need to do the http:// part? Can you just do the www.mysite.com/pagetitle.html?