What does it mean if I'm following someone?
Following a user allows you to see the member's activity (given that their activity is public). A member's activity includes purchases, recommendations, comments, and Collections. It's a great way to show another person that you like their taste, and following them also gives you a way to discover products you might also like.
Activity from people you follow on Creative Market will show up in your personal feed under Activity. Here, you'll be able to see what they like, add to a collection, recommend, comment on, and list (if they're a Shop Owner:)
If you follow Shop Owners, their products will show up in your personal feed on Creative Market (which you can find on the front page by clicking "Following" or "Recent":
How do I stop users from following me?
You can't prevent other users from following you, but you can hide your activity so they can't see your purchases and such. Learn how to do that here.