I joined Helium about 7 years ago and have 112 articles there ... and I'm sorely disappointed for several reasons:
* The revenue is minimal;
* I must constantly return and rate other people's articles in order to have the "right" to make revenue on the site (rating star system);
* I cannot remove an article once posted;
* If I need to change an article, it must go through a peer approval process which means my changes can be refused;
and the most troublesome thing about Helium:
* The Terms of Service includes a "permanent irrevocable perpetual right and licence" ... this that you give Helium permission to use and profit from articles you have posted on their website - forever ... even after you close your account with them.