Category URL Duplicate Content

[MagnetsUSA]

I've recently been hired as the web developer for a company with an existing web site. Their web architecture includes category names in product urls, and of course we have many products in multiple categories thus generating duplicate content.

According to the SEOMoz Site Crawl, we have roughly 1600 pages of duplicate content, I expect primarily from this issue. This is out of roughly 3600 pages crawled.

My questions are:

1. Fixing this for the long term will obviously mean restructuring the URLs for the site. Is this worthwhile and what will the ramifications be of performing such a move?

2. How can I determine the level and extent of the effects of this duplicated content?

3. Is it possible the best course of action is to do nothing?

The site has many, many other issues, and I'm not sure how highly to prioritize this problem. In addition, the IT man is highly doubtful this is causing an SEO issue, and I'm going to need to be able to back up any action I request. I do feel I will need to strongly justify any possible risks this level of site change could cause.

Thanks in advance, and please let me know if any more information is needed.

[MagnetsUSA]

Thanks for the helpful response, Oleg.

So far in examination, pretty much all of our ranking terms point towards a category page, whose URL would not change. While some of our product pages are indexed, very few seem to come up in SERPs. I still worry there might be a ranking drop on the overall site.

We do ok in G for some terms, though not nearly as well as I'd like. I guess fixing other major issues should be a priority.

I think we'll look at using canonical tags and 301's to correct the problem, at least in the short term.

[OlegKorneitchouk]

There are many factors involves and I would really need to see the site/categories to give a specific answer. However:

1. Changing urls will result in loss of rankings. If you 301 redirect from old to new, you will be able to recover most of the rankings but there is ~2 week period where you will drop out of serps.

2. For duplicate content, assuming all pages have been crawled by G, compare you actual # of pages to # results returned by site:domain.com. Also see if there are duplicate title tags (usually results in duplicate content)

3. Tough to say. If G is ranking you well and has been for a while - don't fix what ain't broke. There are many examples of people taking a long time to recover from mistaken 301 redirects or improper canonical tags which tanked their rankings - you're looking to do this on purpose.

that being said, you will probably need a either canonical tags and/or 301 redirects to maximize the site's SEO potential.