Helium describes itself as an outlet for citizen journalists where writers can contribute by writing about topics which they are comfortable with and well-informed. At this community driven site, rating other articles is not only encouraged, but it is also required. This is how they measure how much value you provide to the site.
Helium uses a stars and badges system to award users both visually and monetarily. This tiered structure is in place to also highlight the individuals who are contributing more to the site itself. You must remain an active participant to continue to earn revenue share. Participation is defined as maintaining at least a one rating star. To maintain at least one rating star, you must have completed a minimum of 40 quality article ratings within the last 90 days according to the user agreement. 
There’s some confusing information because over at the stars and badges help pages it says something about needing 30 rates in the last 90 days instead of 40, so I’m not sure which one is accurate. The bottom line means that Helium is not just a place where writers can earn from writing. There’s a significant commitment involved to ensure the community continues to function as a self rating marketplace.
In addition to the standard revenue share that’s based on search engine traffic finding your articles, there are a number of other ways to earn money at Helium. Publishers seeking specific content will post their needs in the marketplace with the assignment guidelines and the amount the writer will be paid in plain view. Writers will compete by posting submissions to the publisher in hopes of it being the one chosen for the job.
The upfront payments and empty title bonus are also ways to make money on Helium, although both of these options appear to have more to do with turnaround time or being first to fill empty titles instead of being rewarded for quality writing. The amount you earn for being first to write for an empty title on Helium is $1 while the upfront payment amounts depend on how many rating stars you have, with the higher amounts naturally going to the more active (higher starred) contributors.
Stock content allows publishers to browse your archive of articles and if one is found that suits the publishers needs, the content is licensed through Helium and you get paid. Helium also offers a number of writing contests where the top three highest rated entries earn some cash. There’s even a writer affiliate program for referring other writers in which you’re paid 5% of the referred writers earnings.
There certainly seems to be quite a few different angles for generating income at Helium, but the writer must really immerse himself into the community and engage in all possible facets of participation to truly reap the higher level monetary rewards. Like most things, if you truly want to succeed, it takes perseverance and dedication to the craft and earning at Helium is no exception.