Hello,<br><br>My first question is if there is a rule-of-thumb or widely-recognized-convention on whether a site should choose to have www prefix or not. Or is it simple a personal preference of the site owner?<br><br>My second question is more specific to my case. I didn&#39;t setup any url redirect, so my site can be accessed by both:
<br><a href="http://www.example.com">www.example.com</a> and <a href="http://example.com">example.com</a><br>Now I learned that from SEO point of view, it&#39;s better to redirect one of them to the other. Personally, I prefer the no-www url, 
i.e. <a href="http://example.com">example.com</a>. However, the site has been up for a couple years, and the two address ends up with different google page ranks.<br><a href="http://www.example.com">www.example.com</a>&nbsp; PR=7
<br><a href="http://example.com">example.com</a>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; PR=3<br>If I were to redirect all <a href="http://www.example.com">www.example.com</a> links to <a href="http://example.com">example.com</a>, will that hurt my PR, say drag it down from 7 to 3? 
<br><br>I also have gsitemap module installed, is there any setup need to be taken care of there, for example, submit the site or generate sitemaps with/out www prefix?<br> <br>I am a newbie on these SEO and page rank stuff, please advise.&nbsp; 
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<br>Thanks,<br>Jim<br><br><br>