But for other communities, moderators review content and remove posts that breach the site's user guidelines. Racist or sexist speech, for example, could get a comment unpublished. Posts that directly target and insult other users could also be rejected.
Most companies also remove unattributed content that could prompt copyright infringement suits.
Pascucci said Mzinga moderators span a wide age-range, and include college students and parents with full-time day jobs who want to supplement their income.
Other companies, however, such as boutique social media firm eModeration, said they prefer older moderators with more life experience under their belts.
Tamara Littleton, CEO of the London-based firm, said that a high proportion of her company's moderators are women who want to juggle raising a family with flexible work. But, increasingly, she said, more men have joined the fold.
Although her company is headquartered in London, 60 percent of its business is in the United States. Littleton said the industry pays moderators anywhere from $8 to $19 an hour, adding that more specialized firms like hers tend to pay on the higher end of the range. Because the field is emerging, it's difficult to quantify the size of the industry.
The moderation business is a billion-dollar industry, Littleton said. But, because it's behind-the-scenes work that people do from home, misperceptions persist about its not being "proper work."
Bill Keller, 48, who moderates for the Emeryville, Calif.-based Lithium from his home outside Kansas City, Mo., agrees.
"When I said I have a job online working as a moderator, [my father and brother] both rolled their eyes," he said. "They said, 'Working online isn't really a job, working from home isn't a job.' I had to convince them it was making money."
Christina Mattoni, 40, a moderator for LiveWorld, a San Jose, Calif.-based social network marketing agency, said that despite relentless myths to the contrary, moderators aren't "paid to surf the Internet and sit in their pajamas and drink coffee all day."
That they're solitary folks who shun social interaction is another popular misperception.
"I do interact with quite a few people on a regular basis through chat and e-mail," Keller told ABCNews.com. "It's not like we don't hear another human being's voice."
In fact, moderation companies say that in hiring new recruits, in addition to looking for people with solid backgrounds in communications and online communities, they favor those who are effective team players.
Moderation professionals emphasize that most of the people who use online message boards, and submit user comments, do so with respect for other users and the owners of the sites. But, they say, just one "toxic poster" can derail a conversation and kill the mood for a whole community.
Sherry Wilcox, 39, a veteran of the industry who works for eModeration from Jacksonville, Fla., said that after more than 15 years in the business, she can predict the direction of the conversation from reading one foul post.
"When you're moderating a site, you know that a discussion is going to go in one direction, and it's not going to be good," she said. "But if you remove that one single post, the whole thing might go back on track."