Additional domain names can be registered for you and hosted so that they work the same as your primary Amped Up website. For example, your primary web site may be www.yourcompany.com, but I can also register www.yourspecialcompany.com and have it work the same way. Some people like to get the .net versions of their domain as well so that nobody else can get them.
More than 5 emails can be set up as well. As these are hosted, they are annual costs.