WordPress and some other CMS systems give you the option to allow indexing of content multiple times based on its association with additional categories or tags.
The short answer is that it’s best to use NOIDEX for categories and tags.
While extra indexing can seem like a great way to get your pages added extra times into the search engines, it’s likely to be viewed as duplicate content and will either be deleted or cause your site to be penalized in the search engines and even marked as spam.
Thinking about this from the view of the search engine, this makes sense. If you build a great page of content and it gets indexed, the search engine should be able to figure out what the information is about and show it to a person when they’re searching for a topic related to your content. So what benefit is there to the search engine to have your same piece of content twice? There isn’t any.
Using NOINDEX in your blog doesn’t mean that page is never indexed. It means that extra copies aren’t fed to the search engine crawler for each category and tag with which the post is associated.
If you want to have a bigger footprint online, the real solution is to keep creating great content.
Do you have any other questions about duplicate content or how to get the best results from your content? Leave a comment below.
Here are a few useful video from Google’s Matt Cutts that will help you understand more about duplicate content and how to deal with it in your marketing strategy.
Do you recommend article marketing as an SEO strategy?
Is the same content posted under different TLDs a problem?
How to structure a site?
How can I make the pages on my site unique?