Update Slack links; start phasing out mailing list

CONTRIBUTING.md

@@ -25,7 +25,7 @@ discussions.
 
 ### Slack
 
-For real-time chat, you can join the **#netbox** Slack channel on [NetworkToCode](https://slack.networktocode.com/).
+For real-time chat, you can join the **#netbox** Slack channel on [NetDev Community](https://join.slack.com/t/netdev-community/shared_invite/zt-mtts8g0n-Sm6Wutn62q_M4OdsaIycrQ).
 Unfortunately, the Slack channel does not provide long-term retention of chat
 history, so try to avoid it for any discussions would benefit from being
 preserved for future reference.
@@ -185,11 +185,5 @@ overlooked.
   sync to review agenda items. This meeting provides opportunity to present and
   discuss pressing topics. Meetings are held as virtual audio/video conferences.
 
-* Official channels for communication include:
-
-    * GitHub issues, pull requests, and discussions
-    * The [netbox-discuss](https://groups.google.com/g/netbox-discuss) mailing list
-    * The **#netbox** channel on [NetworkToCode Slack](https://networktocode.slack.com/)
-
 * Maintainers with no substantial recorded activity in a 60-day period will be
   removed from the project.

README.md

@@ -12,7 +12,11 @@ complete list of requirements, see `requirements.txt`. The code is available [on
 
 The complete documentation for NetBox can be found at [Read the Docs](https://netbox.readthedocs.io/en/stable/).
 
-Questions? Comments? Start by perusing our [GitHub discussions](https://github.com/netbox-community/netbox/discussions) for the topic you have in mind.
+### Discussion
+
+* [GitHub Discussions](https://github.com/netbox-community/netbox/discussions) - Discussion forum hosted by GitHub; ideal for Q&A and other structured discussions
+* [Slack](https://join.slack.com/t/netdev-community/shared_invite/zt-mtts8g0n-Sm6Wutn62q_M4OdsaIycrQ) - Real-time chat hosted by the NetDev Community; best for unstructured discussion or just hanging out
+* [Google Group](https://groups.google.com/g/netbox-discuss) - Legacy mailing list; slowly being replaced by GitHub discussions
 
 ### Build Status
 

docs/development/index.md

@@ -4,12 +4,12 @@ NetBox is maintained as a [GitHub project](https://github.com/netbox-community/n
 
 ## Communication
 
-Communication among developers should always occur via public channels:
+There are several official forums for communication among the developers and community members:
 
 * [GitHub issues](https://github.com/netbox-community/netbox/issues) - All feature requests, bug reports, and other substantial changes to the code base **must** be documented in an issue.
-* [GitHub discussions](https://github.com/netbox-community/netbox/discussions) - The preferred forum for general discussion and support issues. Ideal for shaping a feature request prior to submitting an issue.
-* [The mailing list](https://groups.google.com/g/netbox-discuss) - An alternative forum for general discussion (GitHub is preferred).
-* [#netbox on NetworkToCode](http://slack.networktocode.com/) - Good for quick chats. Avoid any discussion that might need to be referenced later on, as the chat history is not retained long.
+* [GitHub Discussions](https://github.com/netbox-community/netbox/discussions) - The preferred forum for general discussion and support issues. Ideal for shaping a feature request prior to submitting an issue.
+* [#netbox on NetDev Community Slack](https://join.slack.com/t/netdev-community/shared_invite/zt-mtts8g0n-Sm6Wutn62q_M4OdsaIycrQ) - Good for quick chats. Avoid any discussion that might need to be referenced later on, as the chat history is not retained long.
+* [Google Group](https://groups.google.com/g/netbox-discuss) - Legacy mailing list; slowly being phased out in favor of GitHub discussions.
 
 ## Governance