Real-time text chat facilities such as IRC appeared in the late 1980s. Web-based chat and instant messaging software appeared in the mid-1990s. The PLATO computer learning system allowed students to collaborate on networked computers to accomplish learning tasks as early as the 1960s, but the early networking was not accomplished via the World Wide Web and PLATO's collaborative goals were not consistent with the presenter-audience dynamic typical of web conferencing systems. PLATO II, in 1961, featured two users at once.
You can do this through statistics or survey results from your existing customers. Imagine the conversion capability of a statement like, “Seventy percent of customers using our product shaved 10 points off their golf game within a month!” You can just hear them clicking your CTA. Just be sure not to make any outrageous claims—especially income claims. You want to preserve their sense of trust in you.