Stack Exchange Inc. has released an updated, feature-complete version of Stack Overflow which is now available as an Enterprise version. You can request a demo or contact the Enterprise Team through the Stack Overflow Enterprise website to learn more.
Stack Overflow Enterprise is a private version of Stack Overflow, hosted on-premises (or on private cloud) to help teams collaborate, move faster, and share knowledge amongst themselves in a secure environment. The Enterprise version has the same end user experience for developers, but adds in useful features like support for SSO, reporting, and integration with other systems.
Enterprise is a self-sustaining community, built for large organizations that generally plan to support 500 or more users.
If you prefer a more public-facing site, we have 150+ sites to help support your developer community. But if you cannot find a Stack Exchange site in your area of interest, we have a place where you can propose one. "Area 51" is a community-driven process where groups of experts come together to build new Q&A sites that work just like Stack Overflow. You can read more about the site proposal process here.
There is also Stack Overflow Teams for those developers or smaller teams that may have a need for Stack Overflow features but are too small to require Enterprise functionality.