Website url: With or without www?

[Ceres]

I notice some websites use "www" while others don't. From what I understand, using BOTH for your website may cause duplicate content issues with search engines. To give an example, I notice The National Portal of India currently uses http://www.india.gov.in/ and http://india.gov.in/. How important is it for them set up a redirect from url without www to url with www (or vice versa)? Are they likely to suffer from duplicate content if they don't see up a redirect?

Please share your thoughts so that we can all learn!

[Jeff]

I doubt India.gov.in really cares about the search engines!

However, if you're an individual webmaster then every little bit helps. The search engines see India.gov.in and National Portal of India as different pages and your link equity gets split between them. You really need to forward one version to the other to prevent this.