Did you realise that search engines might think these two websites are different?
Removing the www from your website creates a legitimate alternative address to view your page – ensuring that those people who don’t bother to type the www still find your site – but this might confuse search engines, which will see the same content on both URLs.
Because the same content is appearing on two different URLs (on the www and non-www) a search engine might get confused and try to index both of these sites differently. This means that it will treat these two sites as duplicates, and could penalise them in search rankings.
Search engines have to remove duplicate sites from their listings to prevent their search listings all containing identical websites, especially phishing websites which are fraudulent duplicates of a popular site. But for normal website owners like you, who are just trying to make your web content easier to find, it’s an inconvenience.
Which is better? www or non-www?
In terms of SEO it doesn’t matter at all whether you choose to use the www or non-www version of your site. There have been many discussions about which is best, including this article from Ragepank which does a good job of reminding us why the www is useful, even though it takes a bit longer to type into the address bar.
Google have told us that they actually don’t mind whether you use the www or not, but have warned that you must choose one which is the preferred domain.
Redirect to the real version
The best thing you can do is to redirect from one domain to the other, which will prevent search engines becoming confused about which is your preferred domain. The best way you can do this is with a 301 redirect. This tells search engines that the website they were looking for doesn’t reside on the other address, and that they should always look in the new place from now on.
You can also use a 302 redirect. This is fine but it will mean search engines continue to check the alternate incorrect address in future, so it’s not as fast and efficient.