Obviously with one page to work with, there's not really any space to define "Mission Drift" as a concept itself. Mission Drift is a concept in organization where the purpose over time changes. This is typically seen as a bad thing. But Mission Drift can also be an evolution based on the discovered needs of your service population. Last time I went to the YMCA there were people of all ages, genders and denominations exercising, not just the young men training for seminary like their original mission stated. Here's a quick explainer of Mission Drift as a concept.