Document slack channel creation for other projects (#5185)

* Clarify requirements for asking for a slack channel

Signed-off-by: Jorge O. Castro <jorgec@vmware.com>

* Fix some grammatical errors

* Fix hyperlink to cncf slack

Signed-off-by: Jorge O. Castro <jorgec@vmware.com>

* Actually fix link to CNCF slack

Signed-off-by: Jorge O. Castro <jorgec@vmware.com>

* Add clarification on private channels

Signed-off-by: Jorge O. Castro <jorgec@vmware.com>

* Update communication/slack-guidelines.md

Co-authored-by: Irvi Aini <7439590+irvifa@users.noreply.github.com>

* Update communication/slack-guidelines.md

Co-authored-by: Irvi Aini <7439590+irvifa@users.noreply.github.com>

Co-authored-by: Irvi Aini <7439590+irvifa@users.noreply.github.com>

communication/slack-guidelines.md

@@ -3,7 +3,7 @@
 Slack serves as the main communication platform for the Kubernetes community
 outside of the mailing lists. It’s important that conversations stays on topic
 in each channel, and that everyone abides by the [Code of Conduct][coc]. There
-are over 50,000 members who should all expect to have a positive experience.
+are over 100,000 members who should all expect to have a positive experience.
 
 Chat is searchable and public. Do not make comments that you would not say on a
 video recording or in another public space. Please be courteous to others.
@@ -56,7 +56,6 @@ administrators have time. There is no explicit interval.
 
 [Slack Archive Download]
 
-
 ### DM (Direct Message) Conversations
 
 Please do not engage in proprietary company specific conversations in the
@@ -111,6 +110,39 @@ and describe the situation.
 
 ---
 
+## Should you have a channel on the Kubernetes Slack?
+
+The primary purpose of the Kubernetes slack is for the coordination of the
+Kubernentes project. However it is useful for developers and users to have a
+strong ecosystem of channels for related things. Here are some guidelines for
+determining if you should request a channel:
+
+- The channel MUST be Kubernetes related in some way.
+  - Related cloud native projects might be more appropriate on the [CNCF Slack].
+- The project MUST be open source. 
+  - If you are open sourcing a project DO THAT FIRST, we cannot accommodate every
+    organization's open sourcing launch plans.
+  - The purpose of Slack is to organize an existing community, not seed new ones.
+  - Moderators look at contributor activity, adoption and community consensus
+    around a project, otherwise Slack becomes a vehicle for promotion instead of
+    promulgation.
+  - Establishing and maintaining a Slack channel should be an inflection point
+    in a project's adoption.
+  - Requesting a channel means maintaining it on behalf of the project filing
+    the issue, you will be expected to participate and foster a healthy
+    discourse.
+- Channels around commercial services built on OSS projects are allowed.
+  - Users love the value of being able to collaborate around various services.
+  - Keep it classy, on the Kubernetes Slack we're all on the same team.
+- The channel MUST be public.
+  - In order to ensure all channels adhere to our Code of Conduct, we heavily
+    restrict private channels.
+  - We do allow `#...-dev` channels for established projects where a single
+    project channel is too noisy, but please don't create both at the start.
+  - If you need private discussion areas for security-sensitive topics, a
+    project-specific Slack or the [CNCF Slack] may be a better fit.
+- Ask in #slack-admins or file an issue if you're unsure, it never hurts to ask.
+
 ## Requesting a Channel
 
 Channels and User Groups are managed by [Tempelis], a tool that enables external
@@ -375,4 +407,5 @@ Report any actions taken to the other slack admins, and if needed the
 [Slack Config Documentation]: ./slack-config/README.md
 [default message pinned]: ./slack-config/template.yaml
 [Slack’s policy on inactivated accounts]: https://get.Slack.help/hc/en-us/articles/204475027-Deactivate-a-member-s-account
-[moderation guidelines]: ./moderation.md
+[moderation guidelines]: ./moderation.md
+[CNCF Slack]: https://slack.cncf.io/