In her spare time, away from her duties as a chemicals specialist in the Army, Angie Papple fires up her computer and writes an article about something close to her, like life in the military. Other times she'll analyze a piece of software. Or she'll churn out advice for travelers to Hawai'i, where she lives, or Puerto Rico, where she's never been.

Some of these pieces bring her mere pocket change. The most lucrative ones earn about $40. Most of all, though, she's thrilled to be considered a writer.

"It was just a big surprise that someone would actually want to give me money for writing," Papple says. "It really shocked me at first."

The Internet is full of words written for no money at all, just for passion. And it's veined with pieces (like this one) written in someone's regular line of work. Now, though, more and more online copy is being cranked out by a hybrid class: people like Papple, happy to serve as ultra-low-cost freelancers for sites that — unlike many personal blogs — actually get readers.

Greasing the wheels are sites like Helium, ThisIsBy.Us and Associated Content, which dangle micro amounts of pay to amateur writers willing to contribute material. Virtually any topic is open, from advice about child-rearing to an exegesis of mood rings.

These sites hope to accumulate big troves of articles that rank high in search engine results or on media-recommendation sites, then lure ever more readers and advertising dollars. And people are biting. Associated Content and Helium each say they've signed up more than 100,000 writers.

Recently Helium took an extra step to blur the line between amateur and professional writers: It set up a marketplace where third-party publishers — both online and in print — can commission works. That's where Papple has found her best-paid gigs for software reviews and travel writing.

Among the publishers that have been seeking content from Helium's pool of writers is BostonNOW, a free newspaper aimed at public-transit commuters. It recently offered $40 to someone who could churn out a guide to multivitamins that was "comprehensive" — though just 350 words. That same day, an aromatherapy-related Web site was willing to pay $75 for 750 to 1,000 words on the "positive and emotional benefits of body fragrance."

The pay in the marketplace — as high as $300 so far — is way better than the occasional checks that even the most prolific writers can expect from contributing to the main, ad-supported Helium site. But even the marketplace rates would sink the spirits of professional freelancers who try to command $1 per word or better. Indeed, some writers' advocates lament that Helium and other online word mills lower standards for the craft.

Mark Ranalli, Helium's founder and CEO, counters that his site is not out to undermine established journalists or copywriters. Instead he expects to expand the ranks of paid writers to include part-time talent that otherwise would be sitting fallow.

"My next-door neighbor is far more educated than most freelance writers," Ranalli says. "She's home with three kids, but she went to Harvard!"

Ranalli developed Helium to jack into two online currents at once.

One was how easy it was becoming to mine the Internet's lucrative systems (especially the one powered by Google Inc.) for putting contextually relevant advertising along written content. While that model already fueled information-rich sites like The New York Times Co.'s About.com, Ranalli wanted to tap a second big Internet idea — "the wisdom of the crowds" — to make Helium's content exponentially more abundant.

That same principle fuels Wikipedia, the advertising-free online encyclopedia generated by volunteers. But while Wikipedians endlessly redo each other's work, contributions from Helium users remain intact.

That means Helium has, say, 15 separate articles on the American black bear. To make that mishmash useful, Helium asks its community of contributors — excluding the 15 authors of the black bear entries — to vote on which of those 15 articles is best. The top-rated ones rise to the top.

Much of the writing on Helium ranges from awful to marginal. But Ranalli noticed that the very best contributors were actually pretty good. As the site's user numbers kept rising, the thin layer of cream on the top amounted to a sizable number of people.

So he launched the marketplace to let Helium's best writers try to make a bigger name — and more money — for themselves by hooking up with outside publishers, who pay Helium a 20 percent commission. The marketplace launched last fall in a limited manner and expanded this month.