Who is Marjorie 'Slip' McMahon from Angry Housewives Eating Bon Bons and what is their importance?

Marjorie 'Slip' McMahon is a strong, opinionated woman, who has strong feelings about the injustices of the world. She often participates in protest marches and becomes an organizer of the Habitat for Humanity project in the nineties. Slip is decribed as a small woman, who has more personality in her small body than most.