In this paper we present a Collaborative Computing Infrastructure that enables applications that are distributed across a network of computers to collaborate using the Atom Publishing Protocol. The Collaborative Computing Infrastructure couples together, and facilitates interactions between, application programs using the pull-based, event-based distributed computing paradigm. The Atom Server allows publishers to publish events as Atom feed entries for consumers to read. The current specification of the Atom Publishing Protocol, which we have implemented, requires feed entries to be retrieved one by one. To provide better performance, we have also implemented a modification of the Atom Publishing Protocol that supports retrieval of all of the feed entries in a collection at once. This modification results in shorter retrieval times for feed entries, fewer connections to the Atom Server for each consumer, and larger numbers of concurrent consumers.