website: Document Checkpoint. Fixes #340.

website/source/docs/faq.html.markdown

@@ -16,3 +16,16 @@ virtual memory to be allocated. However, in practice the limits are much larger
 than any realistic deployment of Consul would ever use, and the resident memory or
 physical memory used is much lower.
 
+## Q: What is Checkpoint? / Does Consul call home?
+
+Consul makes use of a HashiCorp service called [Checkpoint](http://checkpoint.hashicorp.com)
+which is used to used to check for updates and critical security bulletins.
+Only anonymous information is sent to Checkpoint, and cannot be used to
+identify the user or host. An anonymous ID is sent which helps de-duplicate
+warning messages and can be disabled. Using the Checkpoint service is optional
+and can be disabled.
+
+See [`disable_anonymous_signature`](/docs/agent/options.html#disable_anonymous_signature)
+and [`disable_update_check`](/docs/agent/options.html#disable_update_check).
+
+