Update quick-install.md

Tweaks for clarity.

doc/quick-install.md

@@ -4,7 +4,11 @@ This document describes the required steps for a quick Jitsi Meet installation o
 
 Debian Wheezy and other older systems may require additional things to be done. Specifically for Wheezy, [libc needs to be updated](http://lists.jitsi.org/pipermail/users/2015-September/010064.html).
 
-N.B.: All commands are supposed to be run by root. If you are logged in as a regular user with sudo rights, please prepend ___sudo___ to each of the commands.
+N.B.: 
+
+a.) All commands are supposed to be run by root. If you are logged in as a regular user with sudo rights, please prepend ___sudo___ to each of the commands.
+
+b.) You only need to do this if you want to ___host your own Jitsi server___. If you just want to have a video conference with someone, use https://meet.jit.si instead.
 
 ## Basic Jitsi Meet install
 
@@ -59,6 +63,8 @@ org.ice4j.ice.harvest.NAT_HARVESTER_PUBLIC_ADDRESS=<Public.IP.Address>
 See [the documenation of ice4j](https://github.com/jitsi/ice4j/blob/master/doc/configuration.md)
 for details.
 
+By default, anyone who has access to your jitsi instance will be able to start a conferencee: if your server is open to the world, anyone can have a chat with anyone else. If you want to limit the ability to start a conference to registered users, set up a "secure domain". Follow the instructions at https://github.com/jitsi/jicofo#secure-domain.
+
 ### Open a conference
 
 Launch a web browser (Chrome, Chromium or latest Opera) and enter in the URL bar the hostname (or IP address) you used in the previous step.