At the turn of the twentieth century, ethnic enclaves helped immigrants to find jobs and to adjust to their surroundings. In the twenty-first century, transnational professionals also have other spaces of support: the ‘virtual’ enclaves made possible by new communication tools. Based on interviews with high-tech professionals over the course of an industry boom and downturn, in this article I trace the institutions that affected structures of online help with work. For some engineers from India and Taiwan, alumni ties, maintained by email lists, were important; these transnational workers had an allegiance to their ‘batch’ (university cohort) that the US-born workers lacked. Their far-flung, multi-tiered alumni lists combined the benefits of strong and weak ties: deep commitments and unique information. This study makes a contribution to theorization of immigrant adjustment, social capital and work technologies.