Yesterday Google launched a new feature called Parameter Handling.  It's a variation on a feature that has been available in Yahoo! for quite some time and is a welcome addition to Google Webmaster Tools. Vanessa Fox has a nice writeup on Search Engine Land comparing it to some other options.

You can access Parameter Handling via:
Google Webmaster Tools > Site Configuration > Settings

Parameter Handling allows us to remove some name=value pairs from URLs to canonicalise them. This should theoretically have a similar effect to using the canonical tag, except that we as SEO's managing clients Google Webmaster Tools accounts can make the change 'immediately', benefiting our clients and Google.

At the Web 2.0 Summit 2008 I chatted to Matt Cutts just prior to the canonical tag rollout -  he was really excited about it at the time as it was something he'd been personally sponsoring. While I am a big fan of the canonical tag, its main failing is that the website developer is still required to implement it. I work on lots of the biggest websites in the UK, and getting a canonical tag change request scheduled, implemented and tested by some IT teams could in some scenarios take 6 months to a year. At the time I chatted to Matt I explained I'd really like a more powerful and centrally managed way to control URL parameters (I was thinking bot recognised REGEX and URL rewrites in the Robots.txt) and while Google Parameter Handling doesn't appear to have the full REGEX capabilities I'd hoped for it is a good start.

- "Adjust parameters with extreme Caution!!!"
The main usage for this I see is to remove superflous tracking, affiliate and sort strings from URLs, this should have the benefit of channeling the external and internal link weight to your main desired canonical page...nice.

But...be very cautious when removing other parameters, I have seen many scenarios whereby a parameter that is not required in one location or URL format may be required in another, so making a bad parameter adjustment selection to fix one problem could cause a whole lot more :-( . Removing tracking and affiliate strings used internally and externally should be a safe first step to assess the functionality of parameter handling.

Google: If you allowed REGEX then it would be much more powerful and flexible :-)

- Validating Parameter Adjustment Candidates
Before removing a parameter it is essential to review where and why it is being used. Use the following to show you a list of pages that will affected by a change.

Check each parameters usage using:
[allinurl: parameter site:example.com]

Google: perhaps some direct links to this query from the "Parameters found" list might be good.

- Case Sensitive
It appears that parameters are case sensitive. This makes sense and is the same as the robots.txt protocol, so make sure you add each indvidual variation of a parameter:
campaign
Campaign
CAMPIAGN

- Outstanding Questions:

1) Is Pagerank (internal and external) passed to the new streamlined URL?

2) Does this apply to both internal and external links?

3) Do parameters only show up in Google Webmaster Tools if they are used internally?