<HEAD> customization or using a plugin (which isn’t available on many hosting plans).
Well, good news: in the latest builds of Discourse you can customize all of the text via the admin interface. Simply go to Admin > Customize > Text Content and you’ll be presented with a search page.
Search for the text you want to customize, click Edit then enter the new value. For example, I changed the “Dashboard” link to say “Evil Trout” here on Meta. After refreshing the page the text has been updated:
As always, give it a spin and let us know of any bugs or suggestions and we’ll tweak accordingly!