Rolling out frequent bug fixes and new features to production is common today. Many of these changes are unnoticed by users. However, new features that have a significant impact in terms of usability or performance ought to be rolled out in a phased manner. In other words, deployment should be decoupled from a release.

Simplistic release processes activate new features as soon as they are deployed. This can potentially have catastrophic results, ranging from user issues (swamping your support resources) to performance issues (causing downtime).

Hence, in large sites, it is important to decouple deployment of new features in production and their activation. Even if they are activated, they are sometimes only seen by a select group of users. This select group can be staff or a limited set of customers who get an early preview.