Angie’s List is an Internet-based ratings and referrals organization that collects customer satisfaction ratings on companies in scores of home service categories, everything from plumbing to pet sitting to piano tuning. Roofing contractors are included. Formed in 1995, Angie’s List has been used by more than 500,000 homeowners in 124 cities nationwide, and it is steadily expanding. Most people who use the list pay a modest membership fee, which gives it some tangible value