We consider loosely coupled distributed computing systems in which processes interact through shared resources, which are modeled as bulletin boards. The first part of the paper formalizes the notion of consistent behavior when unreliable processes concurrently access a bulletin board. This model is interesting both as a tool for showing the correctness of a board implementation and also because it provides a mechanism for reasoning about consistency in distributed systems, which was previously lacking. The remainder of the paper discusses software techniques for implementing consistent bulletin boards in a network of processors lacking shared memory. Applications for our approach range from asynchronous interprocess communication to mechanisms for achieving mutual exclusion, deadlock detection and for building distributed database systems.