From the blog
Our model is customers first, investors never

Hosted git repositories

• Annotate your source with links, docs, references, etc
• Public, private, and "unlisted" repositories
• Fine grained access control, including access for users without accounts
• First-class Mercurial support also available

Powerful continuous integration

• Runs fully virtualised builds on various Linux distros and BSDs
• Submit ad-hoc jobs without pushing to your repository
• Post-build triggers for email, webhooks, etc
• Log in with SSH after build failures to investigate further

This CI experience is leagues ahead of all others. Resubmitting builds and SSH'ing in is saving me multiple hours.

— Andrew Kelley, author of the Zig programming language

Mailing lists & code review tools

• Patch review tools on the web
• Threaded, searchable mail archives
• Tools for working with third party mailing lists

Customizable ticket tracking

• Private bug reports and bug trackers for security issues
• Fine-grained access controls
• Participation via email, with or without an account

Task dispatching & service integration

• Automate tasks between various services
• Integrate with third-party services like GitHub
• Reduces the workload for maintainers and contributors

Markdown- and git-driven wikis

• Use git to version control and manage your wiki
• Use any organizational hierarchy you like, a flat wiki is not imposed
• Hosts the detailed sourcehut manual

Sophisticated account management & security

• PGP encrypted and signed emails from each service
• Two-factor authentication with TOTP
• Detailed audit logs of account activity
• Fine-grained third-party OAuth access controls