What is the difference between:

www.moxietype.net
moxietype.net
moxietype.net/index.php
www.moxietype.net/index.php

User might expect all those pages lead to the same page. Search Engines though might store these locations separately. This might result in much lower page rank.

Solution

Decide if you want to keep www or not and make a Global Redirect at your server or write Global Redirect in htaccess file. I prefer non-www as it takes a few more strokes to type in.

Inform Google on Webmaster Dashboard Tools (under Settings) about which version they should keep in their Index. Join Google Webmaster Central if you haven't done so already.

Analyze all the pages in your Web Site and remove duplicate URLs from Google Index by using robots.txt. For example print or category in URL could lead to the same page. You might want to restrict print and category in URL from being indexed. Read about Improving on Robots Exclusion Protocol.