This document summarizes Nu Echo's experience using Erlang to build their hosted grammar server. It describes how they used Erlang and OTP principles to build a high-performance, fault-tolerant, and distributed system with components like Yaws HTTP server, Mnesia database, and Jinterface for Java integration. It also discusses lessons learned around Erlang's strengths in gluing systems together and handling protocols, and weaknesses in string manipulation. The document emphasizes learning and using OTP patterns from the start.