Although social networks are huge (and getting bigger), messaging services have already eclipsed their reach, according to new data from consulting firm Activate. Some 2.5 billion people around the world use messaging services today, with another 1.1 billion due to come online by 2018, the firm estimated. Compare that to social networks, in use by 2 billion people today, with another 400 million due to join within the next two years. For those developers who are thinking of ways to ‘disrupt’ messaging, or at least build apps that take advantage of existing platforms, the untapped market is huge. Although WhatsApp and Facebook Messenger command healthy audiences in most regions, smaller, more local players have exhibited some remarkable staying power. How will these services make money? Activate believes they’ll follow in the footsteps of Facebook Messenger, which has begun experimenting with apps. For those developers debating whether to invest time and resources into a new product that depends heavily on a social network such as Facebook or Twitter, or a messaging service: The latter may develop a sizable audience, and the relative scarcity of messaging-related apps (at least at this point) means your own software has a better chance of gaining short- and long-term visibility. And if you’re interested in building your own messaging service—some tech pros dream no small dreams—there’s an interesting thread on Quora breaking down the resources necessary for such an endeavor. Spoiler alert: It’ll take a lot of infrastructure in order to scale up.