[Nemo]

You can add to someones reputation. It doesn't really do anything for you, but the more people who rep you, the more little green Icons you get. If it is the same as I know it somewhere else, you can click an your control panel and see who has repped you.

You rep somebody by clicking the little set of gray scales at the top of their post. People often rep others when they post something that is helpful to them- such as good freebies!