There are no shortage of bidders on something like Elance for “100 articles wanted for $50″. The people requesting this are interested in one thing only and that is to get their site ranked higher in the search engines. In order to do so their site needs to be Search Engine Optimised (SEO). A big part of the SEO process are articles and their need to contain the right keyword density. What this means is that if your keyword (the thing that is typed in to Google by a searcher) is used repeatedly and randomly throughout the article it will be classed as keyword stuffing and rejected. The right density is required. As an example for a 300 word article you should use the keyword no more than 3 times which equals 1% density.
Now the bidders for these 100 articles requests can easily achieve this and it requires no great skill to do so. The article could be pure junk, poor quality english, full of useless information but still pass the google test. These site owners care little about this as their main site monetisation is probably Adsense whereby they get paid every time somebody clicks one of their sites ads. The sweat shop writers do themselves no favours at all and do nothing other than ensure the quality of web content remains low.
The internet is, or should, be about the distribution of useful and helpful information and become an informative and enjoyable experience for the reader. Writing good quality SEO articles is a skilled job and deserves fair compensation, it’s a case of pay peanuts – get monkeys.