Do I miss traffic (thus, page value) by using the GWMT Parameter Handling Tool?

[johnnybgunn]

I'm working through duplicate content issues. The tracking code or the session id in the URL is being recognized as a different page than the original. Example:

www.example.com is dup content to www.example.com?_nk=x&ad=y&_ga=z, which is tied to a marketing campaign

If my setup in the URL parameter tool is set to: Effect = None  Crawl = Representative URL, then do I:

1. Miss all the traffic being driven to the ?_nk page?
2. With a Rep URL, there still would be two indexed listings:  the .com & the .com?_nk...right?

Neither is good.  Redirects of all the URLs is not an option b/c there are hundreds of these that would need to be redirected. And I also don't want to slow down page load time with excessive redirects, which has been the case when adding 100+ redirects for the recent website migration we did.

[GlobeRunner]

You really should be using Google's parameter tool if you do NOT want those pages crawled.

If they are crawled, and you use the canonical tag in order to tell Google to pass any "juice" to the page you're setting the canonical tag to, then you won't lose any traffic. Both of those URLs (the one with the parameters and one without) essentially will be crawled, but won't be indexed.