Its applies to everything: friends, job, almost all relationships and even using internet.
Either you use your friends for enttertiment or they use you for fun.
Either you use your job to do as little as you can to get paid or your job uses you to do as much as they can without paying you more.
Either you use women for sex /chores/money(if you are chad) or they will use you for chores/money/ sex(if you are chad).
Either you use internet as knowledge base and getting useful information or internet use you as yet another user that will bring money - more addicted he is, more money from ads he brings.