Touchpoints and velocity are a not straightforward metrics, let alone simple. Their purpose is to "draw the golden path" to the perfect interaction pattern. Or in other words, these metrics make the recipe for building the right relationships with the company's customers: when, how and how much you need to interact with your customers to successfully achieve what needs achieving.
Touchpoints traditionally refer to the stage and the mean of communication used to interact with the customer or the prospect.
For example, 1st or 2nd interaction, done via email, a meeting, a demo, or a phone call. The velocity tends to refer to the gaps between interactions and the general number of touchpoints used with a customer or prospect to achieve a certain goal. Relentlessly measuring and iterating on these metrics will eventually allow companies to capture their "repeatable-success-patterns" which can lead to exponential growth.