i had the unfortunate experience of delegating an article writing work to someone, only to find out that all he did was copy paste some article he found on the web. lucky thing was he did it for me for free. ConstantContent pointed out the duplicate to me (thanks ConstantContent), but had already left a negative impression of my site. so how do i check that an article written is not present already somewhere on the internet?
Yeah, search google (and Yahoo/MSN) for a phrase from the article with quotes round it. eg search for "some sentence from the article". This is how I find out how many times my articles are indexed.
copyscape.com or you can just search a portion of the article body in google, making sure to use quotation marks for an exact match/