www vs. no www in backlinks

www. is essentially a subdomain of your main domain (no www.) so they often get treated differently. I do all my backlinking to the root domain (no www.). As long as you're consistent your efforts will be rewarded.

Same as the above two Warriors, no www for me as well.

You can also use .htaccess or web.config to redirect all non-www TO www. This effectively consolidates those links to whichever you choose. Then it just doesn't matter

Google was "supposed to" have taken care of this years ago, but it never seems like the quite get it right.

As others have pointed out, you want to "canonize your URLs":
http://www.google.com/search?sourceid=navclient&ie=UTF-8&rlz=1T4GGIH_enUS274US274&q=how+to+cannonize+urls #num=10&hl=en&rlz=1T4GGIH_enUS274US274&&sa=X&ei=7U ikTKayO4b4nAf0gIWRAQ&ved=0CBIQvwUoAQ&q=how+to+cano nize+urls&spell=1&fp=d48dbafb5c0f783d

And, I try to always use the www for a couple of reasons:

- Most other webmasters tend to use the www if they are linking to you. But...This isn't a true as it used to be.

- The majority of forums and blogs automatically convert URLs that contain the www to links:

google.com
www.google.com

If you use the www, others will also be more likely to use it when they post to forums, blogs, etc.

But again, canonizing your URLs is still the best option, instead of counting on Google to figure it out.

Well, for myself.. I prefer to have the www. in the domain.

But, probably the best thing to do is see what google thinks of your site by typing your domain in. site:domain, and see what they have..Stick with the url that is already ranking and indexed.

Doesn't matter. Just make sure that the link points to the correct URL...whatever it is.

Past that, Don't worry about it.

Canonicalization is important to Google and I can tell you why it makes a difference in one of my recent works for a client.

The site was a PIPS hosted at H4P. The standard PIPS with a HTML markup blog. The link structure for most of these sites is a mix of non-www and with www. The permalink structure was date/pageid. All very confusing to search engines and usually results in ignored links.

This owner of the site wanted to keep the PIPS as a front end. They wanted to replace the old blog in a sub-domain with a new WordPress blog in a normal folder. All easy to do. However, all inbound links (backlinks) would be broken because the links would point to the www.subdomain.maindomain.com and/or subdomain.maindomain.com. Whereas the new links point to www.maindoman.com/blog. In short, the backlinks were a mix of links indexed by G for years and were a mix of non-www and www.

The above is typical of the majority of PIPS sites I personally webmaster for PIPS owners. If you are a PIPS owner you might be interested in what we did next and the positive difference.

As most already know - backlinks increases G PR. The G indexed backlinks for this site are a little less than 5,000! If we were to install the new blog in a the new location the result would be a little less than 5,000 broken links and those links would be de-indexed by G over time.

The solution is three fold.

First, we adhere to the W3 standard and create a 301 redirect. This tells all of the search engines to re-index as that there is a new and permanent link, i.e. old link changed to new link. "Hello Bot, heads-up, I am changing the links on my site, so get busy."

You can do this with the .htaccess file or through Cpanel Redirect using the wildcard. We do it with both, but we do it through Cpanel first because this glues the change(s) at the server level. Technically, all changes at the server level, when W3 compliant, the search engine bots will adhere to in a very short period of time compared to the .htaccess that is essentially a file in the domain structure that affects "only" that domain. It is important (htaccess) and plays a major role later, but best practice is to always work first with the device (server) that directly affects your domain before any and all major domain changes.

Second. We also create the .htaccess and make sure all links are do-follow except for links (pages) that we do not want the bots to index. This is a major change in the role of the domain as mentioned above. In short, when the above was implemented there was a flury of activity by the 5 major search engines within the first 24 hours. Again, this is a high PR site for a PIPS - consequently moved to HG. The content on this site is exactly what G prescribes.

Third. Site Maps. Two site maps were introduced anew. These maps point the bots to the content that we want indexed. The first map (Google XML Map) was a re-code of the front end because it did not point to the new blog. Easy to do. The second XML Site Map located in the root of WordPress and a popular WP plugin does the job nicely.

All of the above was pre-planned specific to this site to include use of Google Webmaster Tools. In short, Google was scanning this site heavily and throwing back all sorts of URL alerts. That is what it is supposed to do and this is good for G and this site. Knowing from experience there would be alerts to URLs that did not adhere to G's standards we took the links and found the usual reasons why the URLs were to be ignored by Google. Most were a combination of non-www and www links. In this case, Google will ignore those links if the "full link" appears to point to the same content. Remember the 301 redirect and htaccess? Now we have a decent percentage of the links that G finds confusing to its search engine visitors and more importantly the actual links. Some where simply broken at EzineArticles from when EA first hit the net and URL linkage was in the work, others were simply sites that were no longer on the net, but the important links to this site were the links that G would ignore. We fixed those easily enough by introducing categories in the old URLs and instructed G to ignore the old links. All-in-all less than 150 backlinks ignored of almost 5,000. Good results. The end result is the new links were indexed within 14 days.

The front end of the site this date is still the same high PR - no loss - and it is indexed regularly. The blog is scanned daily (multiple times) and new content is indexed within an hour.

Bottom line #1 for SEO = First page of Google for a new blog on an existing site. The old blog was usually on Page 2 most of the time.

Bottom line # 2 for Sales = The blog is actually making more sales than the front end, but the old blog seldom made sales at all.

Jeffery 100% :-)