It lowered barriers to entry, by providing well-defined tasks and the resources needed to undertake them; it created a research community with shared goals and assumptions; and, perhaps most important, it offered proof of gradual progress that could be used to justify stable funding for speech and language technology development over several decades, even when no "killer app" had yet emerged.
of this demonstrated success, DARPA's investment in Human Language Technology continued, and grew to include text retrieval, information extraction, topic detection and tracking, summarization, machine translation, and many other problems.