Hi! First, let me say I'm super excited to have you! My name is Jackles and I'm PA's resident nutjob. They love me though. RIGHT GUYS!?
Just so you know, karma isn't really a system that has any purpose more than the occasional indicator about a post. Most of the time, karma isn't used, but if you feel very strongly about a post, that's usually when it is used.
House points was explained. Thanks Nick! And as Cec said, class regularity fluctuates with the activity of the professors, but also the students. The best way to keep classes going is to just post in them, really.
Jobs aren't just shops. The full jobs list is
here. Jobs simply help flesh out your character better. Some jobs, like authors, will not actually need to be developed in character, but are sort of just apart of your character. Others require participation - such as working in the Ministry or Mungo's. PA is always looking for more activity in jobs. When you decide on a job for your character, the best thing to do is PM the supervisor (or if you choose something on the misc. list, then someone already doing the job) to see what needs to be done. If you are the boos/owner/manager, PM an admin to ask for assistance, or just get to it.
I hope that helped! If have any other questions or want to RP, feel free to send me a PM! I love helping out our new members!
-Jackles.