The karma points you earn when you post an answer are actually for "effort".
When you post an answer on Socratic you automatically receive
Think of these points as a "thank you" for putting in the time and effort to answer a question.
Now, if this answer turns out to be really helpful to students, you receive extra karma points. These karma points come from actual "likes" students gave your answer - more on that here:
This is what that little red heart located at the top left of the answer is for - to give people "likes", i.e. karma points, if you found the answer helpful or simply enjoyed reading it.
If your answer is incorrect to begin with, it will probalby be flagged for inaccuracy just to let students know that the answer could be incorrect.
So, to sum this up, you get the initial karma points for your effort and willingness to help students by posting an answer.
From this point on, any karma points you receive for an answer you posted will come directly from the students and depend on the quality and accuracy of your answer. :)