You can write on virtually any subject. There are literally hundreds of categories. Here's just a few of the main categories. There's dozens of sub-categories under each one.

Internet and Business
Investing
Insurance
Writing and Speaking
Communicaations
Relationships
Health and Fitness
Automotive
Cancer
Arts and Entertainment
Book Reviews

Well, I think you get the picture. You can take a good look if you like at: http://ezinearticles.com

If you strategically sprinkle key words throughout your article, you'll develop great search engine results for people looking for ideas on your subject

There's even a blog ( http://blog.ezinearticles.com ) to help you not only submit your articles, but to help you write and structure your title, key words, excerpt and body of your article.

They even have tutorial movies to help you navigate the site, submit articles and a host of other opportunities available at EzineArticles.com. Here's an example of a tutorial movie on submitting an article.
http://media.ezinearticles.com/v/submit-article/submit-article.mov

Writing skills and exposure are essential to any internet marketing endeavor in the 21st century. Ezine Articles is an exellent path to both.

Till next time....