Writing content on “spec” has become a viable business model for many freelance authors. One driver of this phenomenon has been the availability of a marketplace where authors and content buyers can trade. Constant Content and Associated Content are two sites which, on the surface, appear to be quite similar. However, as marketplaces they are a distinctly different experience. Both sites are fairly old in internet terms, having been around for approximately 3 to 5 years. They are both well ranked by google.

Here is what Constant Content has to say:

* Over 10,000 registered writers with different styles and expertise.
* We check every article for grammar, spelling, and even quality.
* We check every article for originality and plagiarism.
* Articles posted to CC are never indexed by search engines to ensure originality.
* We have private and public request systems where you can communicate directly with the writer or writers.
* Many licenses are available depending on your needs.

And heres the pitch from Associated Content:

Associated Content is an Open Content Network.

AC’s platform enables anyone to participate in the new content economy by publishing content on any topic, in any format (text, video, audio and images), and connects that content to consumers, partners and advertisers.

* Content Producers benefit in three major ways beyond the opportunity to publish: fair payment compensation, online discoverability and distribution through our partner sites. Anyone can become a Content Producer.
* Associated Content publishes authentic, useful and informative content on nearly every conceivable topic, produced by real people sharing real-world expertise from diverse perspectives. Search our library to see what we have, or create an RSS feed of content that interests you.

Although both sites have a section for multimedia content such as video, photography and illustration, judging by the site stats most of the action takes place in the writing section and some of the top authors seem to have a very respectable sell through rate.

The approach to sales and the resulting traffic shows a remarkable difference however. Associated Content (AC) accepts advertising while Constant Content (CC) does not. The daily traffic to CC is a mere blip on the map compared to the volume AC draws.

According to demographic research by Quantcast:

Constant Content reaches fewer than 2000 U.S. monthly people.
The site appeals to a young adult, fairly wealthy, primarily female, college educated crowd.

Associatedcontent.com is a top 250 site that reaches over 8.6 million U.S. monthly people.
The site is popular among a slightly more female than male group.
The typical visitor receives Mothering magazine, reads healthboards.com,
and frequents metafilter.com.

I suggest you check out both sites and see which one best suits your style.