I never thought about this before - but I have a client's landing page that has listed in the SERPs as: abc dot com - however, I backlink to his landing page as www.abc dot com. Should I backlink to his site the way it is listed in the SERPs (in other words - drop the www) or does it really matter?
it is not wise to link to a site using both www and non-www version of the url. this will make your seo campaign hurt. your client needs to setup 301 redirect using htaccess file to direct the urls to a single url version
Just pick one version and build links to it. If you build links for both,you'll end up splitting the page's PR and organic rankings.
The thing to worry about here is duplicate content. Pick oneway with or without the www. You should also think about PR sculpting. if you are using more than one URL for the same content, you are not maximizing your PR for that page. While PR doesn't help SERPs, its still beneficial in how Googlebot follows your content. Bottom line is that you don't want to confuse the Googlebot.
Seems google deals with domain with www and without www as different sites. So I think you'd better keep one form and build links for that form.
Its pretty much SEO 101 to make sure you don't have canonical issues. Which means you don't want both the www and non www version of the site in the first place. It's the first thing I check when I take new clients. hope that helps, Nigel