Search Refinement URLs

[BrandLabs]

My site is using search refinement and I am concerned about the URL adding additional characters when it's refined.  My current URL is: http://www.autopartscheaper.com/Air-Conditioning-Heater-Parts-s/10280.htm and when someone chooses their specific year, make, and model then it changes to: http://www.autopartscheaper.com/Air-Conditioning-Heater-Parts-s/10280.htm?searching=Y&Cat=10280&RefineBy_7371=7708\.  Will this negatively affect SEO for this URL?  Will the URL be counted twice?  Any help would be great!

[john4math]

The URL can be counted twice and this is duplicate content.  If Google sees a link to that second URL with the parameters on the end, it won't assume it's the same page as the page with the URL that doesn't have the parameters.

A few things you can do to mitigate this:

1. In Google Webmaster Tools and Bing Webmaster Tools, if those parameters never result in unique pages, you can tell each search engine to ignore each one of those parameters.  If you ignore all of those parameters within webmaster tools, the second URL example above will resolve to the first URL in their eyes of each search engine.
2. You can set a rel canonical on all of your pages to the root page URLs.  Then no parameters will ever affect the indexing of your pages.

I'd be a little wary of setting rel canonical on all of my pages (I don't do this so I can't report if it works or not), so I'd personally opt for option 1 and not option 2, although theoretically each one should solve the problem.