Article directories were widely used to syndicate if you will, information before the inception of rss.

• In return for an article, an author could use what is known as a resource box which contained a brief biography and a link back to any site.
• Depending on the directory in question, this can also point to an internal page.
• Persons who couldn't write their own material, would copy the article including the "resource box", and host it elsewhere.  This process would help to keep readers on their site and leverage the intellect of others.
• Submitting to such article directories, can increase your seo pagerank™ and may even bring extra traffic. This doesn't apply as much now as before.
• To prevent any loss from Duplicate Content penalties, ensure that the engines or most of the important ones, have already indexed the article on your own website, first.
• Some directories will allow the use of anchor text, which is beneficial.
• Don't expect mass proliferation, but consider the worth of using their P.R.  to rank well for a term, if your site is new.
• There is little to stop a seamstress from Scarriff, County Clare from promoting a small business by writing some "stuff" about fabrics. Likewise for a blocklayer from Bandon and his offerings on the advantages of a pointed trowel?
• Reproduce results to the maximum - Increase the content of your site, and gain I.B.L's at the same time.
• These databases are often scraped as well, so don't be too surprised to find your content on all kinds of dodgy and irrelevant sites, and without your backlink.
• To check for Plagarism, scraping or honest use; you can simply paste a block of the text into the search engines or paste your url into the likes of www.copyscape.com