dCycle is a dev-stage-production workflow for developing Drupal sites.
dCycle defines workflows for deploying features and configuration, not content.
dCycle is not a software product. It is a series of step-by-step procedures and standards.
dCycle is really quite simple: three text files which define step-by-step procedures for setting up a dev-stage-prod environment, developing features, and some standards which all stakeholders should abide by. That's it. Often, though, I have found that my colleagues have great workflows, but there's no centralized place to document them, which causes considerable pains in being productive on a site.