Add telemetry docs

Author: knolleary

docs/telemetry/index.md

@@ -0,0 +1,105 @@
+---
+layout: docs-user-guide
+title: Usage Telemetry
+slug: telemetry
+---
+
+
+Starting with the 4.1.0 release, Node-RED gathers anonymous usage information once
+a day and shares it with the Node-RED team.
+
+This information is only shared with the Node-RED team once the user has opted
+into sharing their information. If the user declines to share their information,
+nothing is sent back to the team.
+
+### Why?
+
+Historically, the only measures we've had around the size and scale of the Node-RED
+user-base have been secondary indicators, such as high-level statistics provided
+by npm and docker, or the general level of activity on the community forum.
+
+This does not give us much useful information to help understand Node-RED usage;
+such as what versions of Node.JS are being used, what operating systems are favoured.
+
+
+### What data is collected?
+
+With the 4.1.0 release, the collected information is:
+ - A randomly generated instance identifier to allow us to de-duplicate reports
+ - Node-RED version
+ - Node.JS version
+ - OS type/release/architecture
+
+It does **not** contain:
+ - Any personal information
+ - Any flow configuration information
+ - Any user-specific information related to security
+ - Any information outside the scope of Node-RED
+
+### How is the data collected?
+
+If the user has opted to share information, a task will run 30 minutes after
+Node-RED starts (or when they opt-in), and every 24 hours after that.
+
+The data is sent over HTTPS to an endpoint hosted by the Node-RED project.
+
+### What happens to the data?
+
+The reports are aggregated into a daily record of usage. The individual reports
+are kept for up to 90 days.
+
+### Who has access to the data?
+
+The raw data is only accessible by the core Team Committers.
+
+The aggregated data will be made available on a public dashboard for public
+consumption. _Note_: At the time of writing, we have not yet released this feature,
+so we have very little data to start building the dashboard with. Once it is available,
+this document will be updated to link to it and it will be publicised within the community.
+
+### How do I opt out?
+
+We hope you'll share your information to help us maintain the project. However, 
+if you want to opt out, there are a number of ways to do so.
+
+#### Editor Settings
+
+The first time you open the editor for Node-RED 4.1 or later, if you have not
+already opted in or out, you will be asked if you are willing to share your information.
+
+You can change you made via the Editor Settings dialog at any time.
+
+#### `settings.js` file
+
+You can also enable/disable telemetry via your settings file.
+
+If you have a preexisting settings file, you will need to add a `telemetry` section.
+For new installs of Node-RED, the default settings file already has this section, but
+with the `enabled` option commented out. Remove the `//` at the start of the line
+and change the value to `false`:
+
+```
+    telemetry: {
+        enabled: false,
+        /**
+         * If telemetry is enabled, the editor will notify the user if a new version of Node-RED
+         * is available. Set the following property to false to disable this notification.
+         */
+        updateNotification: true
+    },
+```
+
+#### Other
+
+You can also disable telemetry using the `--no-telemetry` command-line flag, or by setting
+`NODE_RED_DISABLE_TELEMETRY` environment variable.
+
+### Update notification
+
+With the usage telemetry feature enabled, in response to sending the information, Node-RED
+is notified when there is a new version available. This will generate a notification
+in the editor tp help you know when its time to upgrade.
+
+This notification can be disabled via the `telemetry.updateNotification` setting in the
+settings file; it cannot be disabled from within the editor.
+

docs/user-guide/index.md

@@ -30,6 +30,10 @@ title: User Guide
 - [Configuring Node-RED](/docs/user-guide/configuration)
 - [Command-line Admin](/docs/user-guide/node-red-admin)
 
+### Usage Telemetry
+
+ - [Usage Telemetry](/docs/telemetry)
+
 ### Advanced
 
 - [Embedding into an existing app](/docs/user-guide/runtime/embedding)
@@ -44,4 +48,3 @@ places you can do so:
  - Subscribe to the [blog](https://nodered.org/blog/)
  - Follow us on:
     - Mastodon: [@nodered@social.nodered.org](https://social.nodered.org/@nodered)
-    - Twitter: [@nodered](http://twitter.com/nodered)