Firstly, you should know that what "Classification / Categorization" actually mean.

Classification / Categorization: Sorting, labeling, Placing and maintaining objects & data in their classes or categories based on their attributes or features.

Dear Employer, If I say in simple way, I have "Classification / Categorization" skill practically. And I can do two types of works by my this Skill which I named "Technical Works" and "Educational Works". Technical Works donates all types of works excluding educational works which consists of technical phenomena. Examples of technical works, we can take are Categorization, Tagging, Sorting and more which are related to above skill. And "Educational Works" donates Writing, blogging, teaching about Categorization, Tagging, Sorting and more etc. 

Summary:

So, In short I can do all kinds of Educational and Technical works with the help of my "Classification / Categorization" skill.