www versus no www

I'm getting different PRs

[surfgatinho]

I'm finding sites I have show a different PR when I use the www prefix and when I don't.
What concerns me about this is I'm thinking half the links out there use one and half use the other. Is this in effect splitting my PR in half.
Also why does this happen? Surely it's not to hard to regard the two as one in the same

[Marcia]

To eliminate any confusion, try to get links changed to make them consistent to one, and use mod_rewrite to get it all to just one of them - www is most common.

Do a site search (top of page) on mod_rewrite and url redirection; there's plenty of discussion here with instruction on how to do it and links to the official documentation.

[Wired Suzanne]

A new url means a new site and get indexed again.

My site is indexed with www and without www. And the pages were indexed with all kinds of '?...' user tracker codes. Whatever people used to link to me was indexed. And all these pages had a low PR (Split PR). Finally I asked all the linkers to link to me with the exact same URL. Now I have fewer URLs indexed, but with higher PR.

Google indexed 6000 pages of my site, while my site has only around 2500 pages.......

Be aware of this before you start a linking campaign and decide how you want to be indexed.

[jonknee]

FYI, mod_rewrite won't do much for you. The URL stays the same, but the content changes. Since the content is the same for www and no www, it will make no difference.

[Marcia]

A 301 permanent server side redirect (mod_alias) redirects directly to the new page. No problem with those so far.