How do Tibetans themselves conceptualize being Tibetan? Here, I explore this question through an ethnographic illustration of recent public discussions between Tibetans online, and the kinds of reactions these exchanges provoke. Their discussions were often about purity—what makes someone a pure Tibetan? Purity was needed, argued many, to preserve the Tibetan identity. For Tibetans inside and outside Tibet, preservation was a project that Tibetans collectively began after the Chinese invasion. Many saw purity as necessary to promote the project of cultural and identity preservation in colonized Tibet and exile-diaspora. Purity offered possibilities for survival and continuity of the culture. But what does this purity look like?