Reddit glossary
What is Karma farming on Reddit?
Karma farming is posting low-effort content only to collect upvotes and raise a karma score.
Reposts, memes and easy questions are the usual tools. People then use the score to get into communities with karma limits.
Many mods dislike it and some communities look for it on purpose.
If you are promoting something
It can give you a number, but not trust. Readers can see your history, and a history full of empty posts does not help when you later recommend something.