Comment on WordPress SEO Tutorial by SEO Dave.
WordPress categories can gain SERPs in their own right, I link to my categories all the time from relevant pages. What I link to/from is based on what the content I’m linking from, regularly link directly to categories on other sites I own.
By default there’s not much SEO you can add to WordPress categories unless the theme you use takes advantage of WordPress features like under Categories (Posts >> Categories) you can add some descriptive text to the top of a category where you could add some SEO’d text (shame they don’t allow HTML, spent half a day looking for a code fix for this feature a while back). Update: Stallion responsive includes the ability to add content to the top of a category, see the WordPress SEO tutorial category for an example.
You can also use the WordPress Excerpt form on the Post Edit page (if you don’t see an Excerpt form click Screen Options top right and tick Excerpt) to write a category optimized version of an excerpt for each post.
If you have the meta description tag turned on the excerpt you add there will also be used as the meta description for that page as well, so your Google description might use this text.
So you can completely rewrite what your categories show. I never seem to find the time to get around to doing this, story of my life spend days adding features to Stallion I never get around to using :-)
Then there’s widget areas on categories (all pages) you can use the Stallion widget display plugin options to show widgets only on specific categories, so there’s a lot of SEO you can add to categories with Stallion.
BTW copying articles from places like EzineArticles is highly unlikely to create a high traffic website, all you are doing is sending link benefit to whoever wrote the articles for very little gain. Unless you are playing a numbers game with dozens/hundreds of autoblogs filled with scraped content on throwaway domains it’s a waste of effort. I’ve got a small number of autoblogs (for testing), lucky if a PR4 autoblog with 5,000 posts makes over $200 a year: if the content was unique could make thousands of $USD just from AdSense.