Just a few more details:
The RAK group (random acts of kindness) is a group where people can request cards (or other stuff but generally cards) for someone and/or fulfill requests for cards. It has several sub-groups (these are the ones I can remember off the top of my head): BRAK (birthday RAK where you send members (of your choosing) birthday cards, Wish-RAK (where you "wish" for stamped images, punches, ribbon, brads, paper, etc) and fulfill wishes of others (which allows you to make more wishes). There are special challenges and other activities which you can choose to do when/as you desire. It's a ton of fun.
In the
sign up thread for the next DSS round (divine secret sister's) group there is a mini-faq with great details/info.
Both groups are a lot of fun and a great way to get to know people, learn new techniquest, get exposed to different styles, etc. Also, when you join the group(s), there will be threads with all the details (but I understand completely the need to know more before you join and/or commit to something).