They are a way for other people to show their appreciation of you, by clicking on the thumbs-up hand on your posts to raise your karma. You will see that really helpful people such as Fiona have lots of them.
You can also click on the thumbs-down one to lower someone's karma if you are cross with them. I lost two karma points in one day recently and I still don't know who I offended.
I have called you all in to the drawing room because one of you took two karma points from sexysadie. Fiona is the prime suspect but it is circumstantial evidence. I shall list the known facts in my bundle and summarise them in my evidence-in-chief which will take you all no less than 18 weeks to read if you spend that time only looking at the pictures and the pop-up sections. I am particularly proud of my scratch 'n' sniff form E ... etc, etc.
Chris, thank you for the Karma point, I could really do with that new toaster!