A challenger approaches! With any small group of friends, it can be cool to make a little splash when a new friend joins the group. 

Anyways, if you're the accommodating présentateur type, you can choose which text channel you'd like to display these welcome messages for newcomers. It's a pretty simple process:

Step 1: Open Server Settings:

As long as you have a role with the Manage Server permission enabled, you'll have access to the welcome messages function:

Step Two: Overview page:

The welcome message settings are in the first tab of the server settings page, labeled Overview.

Step Three: Select Text Channel

You can select which Text channel to be your welcome channel from the dropdown menu in the System Messages Channel section.

If you don't feel like announcing a fanfare anytime a new friend comes around, just select the No System Messages option at the top!