Online resources are often described and evaluated in terms of their ability to serve vast amounts of diverse content to wide audiences, but well targeted, specialized digital projects can have a profound effect on an academic discipline. The Thesaurus Linguae Graecae®, a digital corpus of over 12,000 works of Greek literature ranging from the ancient era to the modern age, has proven its value to scholars and has been able to convert that value into a sustainability model that incorporates multiple revenue streams. The resource is targeted toward academic classicists and medievalists, who rely on it as the only comprehensive body of historical Greek language works available online; it also offers a small Open Access selection of canonical Greek works for use by a wider audience. The project, which is hosted at the University of California, Irvine, depends on three main revenue streams: subscription fees, direct financial support from the university, and a project endowment. The endowment was originally intended to supplement the other two revenue streams, but the project’s goal now is for the fund to some day cover all of the ongoing costs for the TLG. This case study looks at some of the questions facing the TLG and outlines the broader implications for other resources with highly specialized content: How does such a project build an audience and keep users excited and engaged? What characteristics make a project a strong candidate for a subscription model? And how do the leaders of the TLG envision their resource, and its funding, evolving in the future?