Middle of the Funnel (MOFU) is the mid-point of the funnel, sitting snugly between TOFU and BOFU. Leads that make it to the middle of the funnel are beginning to engage more in the marketing campaign, and would be the point where the product could start to be introduced into the marketing messaging.
If you are running marketing automation, then users who have made it to the MOFU would have been attributed more points based on their behaviour. If you were working on a point scoring scale of 0 to 100 you would expect the users to be between 30 and 70 points.