Why do you have to type www for some sites but not for others?

thanks

Because the 'others' haven't defined the non-www in their DNS.

I believe that the LadynRed is correct(They have not defined it). They have tutorials to automatically add it to the url though so it doesn't split your page rank.

Originally Posted by goheadtry

I believe that the LadynRed is correct(They have not defined it). They have tutorials to automatically add it to the url though so it doesn't split your page rank.

Here is a detailed tutorial about that:
WWW vs. Non-WWW, The PageRank, The Effect And The Solution

I hope this helps.

AHelpingHand,i cant access the link you gave. Does anyone have an article explaining about it (affect on page rank)? thanks.

The issue is www or non www doesn't matter which, but one and one should be chosen and used. The other is generally redirected to the chosen variation for the purpose of proper Domain canonicalization. I have a decent guide to Server Side SEO and URL Canonicalization, in my Blog.

If the www and non www, are not set up correctly search engines will consider it duplicate spam...as you are effectively using both URLs to access the Internet. The same is true for directory indexes, the Domain address and the page address can be a duplicate spam also if not standardized properly. For example www. a domain .com and www. a domain .com/ index.html will present 2 duplicate pages is a default is not set properly.

Peace
Melanie
"Baby"

This is very interesting...the police site for my city has this problem. If you type in the URL without the www, you won't get the site. The site was made with FrontPage 2002 -- does anyone know if the HT Access method mentioned in the tutorial link above would work? I'm not super-savvy with FrontPage. Thanks!

It is becoz of not defined in DNS(Domain Name Server) and its a case of Canonical URL for search engines.

On Google webmaster tool, we have this option to define our website as www.websitename.com or websitename.com

May be the sites you are searching or got, it was not defined as on the both areas....