Earning Potential
In terms of revenue generated per article, Helium pays the lowest among the three sites. It does however have a Marketplace and Contests, which help to supplement a writers income.
Publishing Process
Helium is the fastest among the three sites when it comes to publishing. There is no waiting time between submission and publishing. Zilch. Helium depends on a peer-rating system that asks writers to rate their fellow writers, which eliminates the need for Helium staff to review the articles. Unlike the other sites where you have to click and choose several options, Helium's publishing interface only requires you to click that "Submit" button.
Topic Restriction
Helium restricts topic titles to the ones already on Helium. You may request for a new topic title, though it'll take some time before it gets approved/rejected.
Rights to your Article
Helium claims non-exclusive rights, which means you can still publish them elsewhere.
Payment
Helium offers only one mode of payment, through Paypal. The payout mark is set at $25 and payout is on the 10th day of each month. At the time of writing, Helium is currently looking at the possibility of a check payout option. The option is still unavailable.
Earning Potential
Triond pays the highest in terms of revenue generated per article.
Publishing Process
Triond usually takes less than a day.
Topic Restriction
To quote their guidelines: "Your content must not contain any derogatory, offensive, unlawful, harmful, threatening, vulgar, profane, abusive, harassing, obscene, pornographic, defamatory or tortuous material."
Rights to your Article
Triond claims first rights on your article, meaning they have to be the first to publish it. However, you retain the rights to republish the article elsewhere after it is first published on a Triond network site.
Payment
Triond offers payment through either Paypal, Western Union or check. The payout mark is $0.50 for Paypal, and $50 for Western Union and by check. Payment is made on the 15th of each month.
Earning Potential
Associated Content pays better than Helium but not as good as Triond for revenue generated per article. Associated Content does have an upfront payment option which allows writers to ask for payment upfront. This is however restricted to certain topics and residents of the United States. There are also contests on Associated Content
Publishing Process
Associated Content tends to be the slowest if you are asking for upfront payment. You'll also have to wait to get reviewed even if you're not asking for upfront payment if you have not published at least three times there before.
Topic Restriction
None
Rights to Your Article
You choose. Options given are Exclusive, Non-exclusive, Display only. Exclusive means you give Associated Content full rights to your article. Non-exclusive means you still retain the rights to republish them. Display only means you reserve the rights to take them down when you like.
Payment
Associated Content offers payment through Paypal. Payout mark is set at $1.50 and payout is at the end of every month.
As you can see, the three sites Helium, Triond, Associated Content all have their strengths. Helium has a fast,easy-to-use publishing system set in place, Triond has the highest revenue generated per article, and Associated Content offers to pay you upfront. Try them all and see which one you like.
