Inspired by Sarah Honeychurch's gifting project (and this http://chrisguillebeau.com/postcards-in-the-mail/
and this http://leftysmudges.com/
), a group of us are a part of a project to send each other postcards.
There are no "rules." You can send as many or as few as you like to whoever you like. The topics are up to you. (We also have optional monthly postcard themes, which are published at www.clmooc.com
If you'd like to participate, sign up here. If you do so, your mailing address will be shared with others on this list.