Hipchat provides a comprehensive and searchable chat system for development and customer relations. It is integrated with GitHub and JIRA so our developers can have specific rooms for each project, and we also have rooms for each customer tied into their Twitter feeds so we know what is relevant and can track issues via Nagios alerts.
We use Clojure in several places, most often as a wrapper around other libraries and frameworks (e.g. Hibernate, HAPI, etc.) Our HL7 parsing workflow is heavily based on Clojure with files that look almost like configuration, but actually offer tremendous power and flexibility.