When you use Google (and I guess other search engines) to search for, say, ‘business event directory’, you don’t want to see an entire results page showing the same content from a number of different websites.
What you want to see is a range of web pages offering different content on that subject. Right?
Google knows this, and omits content that it thinks is similar to those that it is already displaying. In the example below, you will see that there is a link named ‘Similar’ next to the domain name for each search result. You can click this link if you are interested in seeing all of the ‘duplicate’ results that it has suppressed.
This has important consequences for your SEO…
If you publish an article that you have written on 10 different websites, then there is a chance that only 1 of them will be found in SERPs for any given search term. Now, if you write 10 different versions of that same article and then publish each to a different website, there is a higher chance that you might fill more of those valuable first page search engine results positions – which increases your chance of being found!
Even better, how about trying to include a slightly different set of keywords and phrases in each article as well?