Rewrite domain requests to prevent splitting the google ranking between two sites

Question

In the top answer in What should a developer know before building a public web site?

one of the SEO recommendations is:

Rewrite requests asking for yourdomain.com to www.yourdomain.com to prevent splitting the google ranking between both sites

Does this work the other way also? I would like to use mydomain.com instead of www.mydomain.com

Answer 1

Yes. You can use any one you want (or any other subdomain.) As long as you use only one.

Though I'm pretty sure google knows that yourdomain.com and www.yourdomain.com are the same anways.

Answer 2

The reason this helps is because google dings your pagerank for duplicate results. If you're hosting www and . then your whole site is duplicated at least once.

Answer 3

You can set a preferred domain using Google's Webmaster Tools.