John Gruber at Daring Fireball writes:: "New social network/recommendation engine, which like Instagram, is debuting with but a single interface: a native iPhone app. The premise is simple and ambitious: you “stamp” things that you enjoy and recommend. There aren’t different types of stamps. There’s no rating from 0-5 or anything like that. Just stamped. What kind of things can you stamp? All sorts of things: restaurants, places, books, movies, music." "Stylish, distinctive, nice-branded UI, too"

Stamped describes itself as:

Stamped is a new way to recommend only what you like best—restaurants, books, movies, music and more. No noise, no strangers, just the things you and your friends love. Read their entire introductory blog post.