There's no advantages of www. or no www. But there are disadvantages of using both, such as spliting googe page rank. Choose one either with or without and 301 all root clicks to with domain.com or www.domain.com
it does not matter that you are not using www or using www only keep in eye relevancy when you do Link exchange program because always check google relevancy of your regular work.....
I like to go with www. - but no extra benefits with or without www. It is not necessary of 301 redirect always. You can choose the proffered domain name in Google webmaster tools with effecting ur site. If not, you should have to do 301. When u build backlinks, it is good to use a same url at all places. Not only url, the anchor u use also have to use in the same style. For example, "search engine optimization" & "Search Engine Optimization" this anchor text difference is also providing by Google in its Webmaster tools. So consider each and every point when u promote a site. All the best.
I also use www because recently i have seen the changes effect without using www! i lost many backlinks in www so i prefer to use www for site stability
jezzz - if you use 301 redirect in place of selecting only preferred domain in Google WMT, you can't loss backlinks.
Google sees www and the naked domain as 2 different sites. A lot of people combine the 2 to get better search engine results. Each to their own.
A minor point... If you really *should* use www then shouldn't somebody tell http://twitter.com/ that they're "doing it wrong" ? Whether you use www or not, just make sure you make sure you direct spiders et al to your "correct" preference and ensure that whichever webmaster tools are aware, you'll be fine
to use or not to use. well it doesn't matter either way as long as when you are building links you use the same with or without. Google will credit your websites links with domain-name.com separately from those with www.domain-name.com
Yeah you should definitely use a 301 redirect. And I got a site with www and a site without and makes no real difference as far as I noticed.
Yeah, www is very important because without 301 permanent redirection search engine will considered your two domain names of your website, so please go through 301 redirection before you promote any website.
I always use w3 because it is a proper way to have more stability. and also follow the 301 redirects.there are some sites which open without using the w3 but i think it is not a proper way to use.