title: Should I default my website to www.foo or not?
body: <p>Notice how the default domain for stackoverflow is <a href="http://stackoverflow.com">http://stackoverflow.com</a> and if you try to goto <a href="http://www.stackoverflow.com">http://www.stackoverflow.com</a> it bounces you to <a href="http://stackoverflow.com">http://stackoverflow.com</a> ?</p>
  <p>What is the reason for this? Not the tech reason (as in the http code, etc) but why would the site owners want to do this?</p>
  <p>I know it's purely aesthetic and I always have host-headers for both www and not, but is there a reason to bounce a user to a single domain, subheaded or not?</p>
  <h2>Update 1</h2>
  <h2>Not having a subdomain is called a <em>bare domain</em>. Thanks peeps! never knew it had a term :)
  Update 2</h2>
  <p>Thanks for the answers so far - please note I understand that <a href="http://www.domain.com" rel="nofollow noreferrer">www.domain.com</a> can point to domain.com. This is not a question about if i should offer both or either/or, it's asking why some sites default to a baredomain instead of www subdomains, or vice-versa. Cheers.</p>
  <p>Jeff Atwood actually HAS explained why he's gone for bare domains <a href="https://blog.stackoverflow.com/2008/06/dropping-the-www-prefix/">here</a> and <a href="https://blog.codinghorror.com/the-great-dub-dub-dub-debate/" rel="nofollow noreferrer">here</a>. (Nod to <a href="https://stackoverflow.com/users/1918/jonas-pegerfalk">Jonas Pegerfalk</a> for the post :) )</p>
  <p>Jeff's post (and others in this thread) also talk about the problems of a bare domain with cookies and static images. Basically, if you have cookies on in a bare domain, then all subdomains are forced also. The solution is to purchase another domain, as posted by the <a href="http://developer.yahoo.com/performance/rules.html#cookie_free" rel="nofollow noreferrer">Yahoo Perf Team here</a>.</p>