I was asked on a blog talk radio interview at whio Dayton what the Craftivist Sisterhood was. I can tell you what it's not and that is it's not a formal group, club or organization. In our case, the reason for the interview, it was three friends who joined together in a spontaneous act of sisterhood to express our feelings through craft. Definition: Craftivism is joining craft and activism but for a longer explanation check out Betsy Greer who coined the term.
Any women who get together and create crafts to express an opinion or address an issue is in the Craftivist Sisterhood. There are organizations you can join such as the craftivist collective started by Sarah Corbett OR you can do what a friend of mine, Johanna Smith, did when she moved to a new state and put out the call to fellow Knitters/crochet and started a Crafting for a Cause group.
Making Good: Five Ways to be a Craftivist