g1smd - 11:24 am on Nov 14, 2006 (gmt 0)

>> In today's world, Google indexes canonical urls. <<

Google tells us that they are trying to, but in many cases they still fail to do so.

When the difference is the addition or lack of a www in the URL, then they are getting things more right than they used to. Likewise if you're talking about /index.html¦htm¦php versus "/" then it is often OK (but could always do with a helping hand).

When the difference is .com versus .co.uk then there are multiple types of "funky result" going on. When the difference is parameter number variations, parameter ordering, or capitalisation issues, then nothing is in place for Google to work out which URL you really intended to be "the one". They take a guess, and the chosen one changes on a regular basis as PR and links slosh about.

If you can set all your internal links to all reference one particular URL format, and you can get all other URL formats on your site to return a 301 redirect pointing to the one format you want to be indexed then you are already miles ahead of the game.

>> The key here is that you should be consistent with internal links within your own site, which makes perfect sense. <<

Yes. That is a key point.

Dynamic sites (like forums and carts) often get this wrong. In fact, poor indexing of those types of sites is nearly always down to duplicate content issues to do with parameter differences, and parameter ordering, not merely simply the fact that the URLs contain dynamic parameters at all.