Many teams are already using Slack as a way to communicate more effectively.

With features like group conversations, private messaging, easy file sharing, and robust search capabilities, this platform can be used to eliminate those one-liner emails that used to junk up your inbox.

But it can also be used in another way.

Some freelancers are finding it’s a great place to build up a profitable referral network—and that their channels can be a means of earning additional income.

A Place to Share

A recent study by Freelancers Union indicated that there are 53 million freelancers within the United States—a population that makes up about 34 percent of the national workforce.

But when it comes to freelancing, an individual can only do so much before reaching capacity. Therefore, freelancers often rely on a network of connections to which they can send projects they simply don’t have time to complete.

It’s true: Research showed that 81 percent of freelancers refer work to fellow freelancers, while 52 percent hire fellow freelancers to collaborate on projects.

Enter Slack. Freelancers within different niches are creating Slack channels in which they can bounce ideas off one another, ask questions, and find reliable sources to which they can direct those overflow projects.

Paying for Access

Because Slack groups are often mini-tribes within themselves, many freelancers have opted for induction by invitation only to ensure that the group remains curated. As a result, members are high-quality, relevant participants who can truly contribute to the group.

Some administrators have even found a way to make their Slack channels profitable—by charging a fee for access.

Paul Jarvis charges $90 a year for access to the slack channel for his Creative Class, as the active community there packs serious value for those on the inside. Participants in this group are able to discuss problems, share ideas and feedback, and hire each other for projects, while also getting an invite to the monthly Q&A call with Jarvis and an industry guest.

Related: 4 Ways to Turn Your Freelancers Into Brand Ambassadors

Thinkster includes access to its Slack channel in the $19 a month pro membership package, which is a space for web and mobile developers communicate with Thinkster authors and fellow members.

Whether it’s a standalone or an add-on item that ups the value of a package, Slack channels are proving to be a means of additional revenue for courses, niche sites, and more.

Low Cost, High Value

For slack channel creators, the ROI of creating a robust platform is relatively high. With the top paid plan coming in at only $12.50/month for annual billing, a single paid user will often more than cover the costs associated with the channel.

Plus, with referral credits and the ‘ Give $100, Get $100’ program Slack has initiated, new users and affiliates benefit from free upgrades (through September 30, 2015.)

Bonus: Paid access also acts as a filtering mechanism for participants. When invitees are required to make a small investment in order to gain access, it increases the likelihood that users will provide and receive value from within.

More than a Means of Communication

What began as a place for simple, fast communication, Slack has taken on an added dimension. Its evolution includes use as a powerful platform for communities of freelancers and creatives to share opportunities and, ultimately, work.

Slack’s motto is “Be Less Busy.” But for those using it as a means of finding new work—it helps keep them busy. And that’s the way they like it.

Related: 4 Strategies as a Freelancer for Winning Better Clients