Why did a couple of college professors become interested in Les's program?
They became interested because the blackboard caught their attention. Since both were college professors who used blackboards, they thought the program might be something like what they taught. That initial recognition led them to become really interested in the program.
Les explains that a couple wrote in after going through their channels, and what caught their attention was the blackboard. Because they were both college professors and used blackboards, they supposed maybe here comes something like what we teach. As a result, they became really interested in the program. Les also notes that God will use all kinds of things to get people's attention.