If you want you to have a fully branded experience, you should use your own domain for Teambox.

You can configure your domain to set up Teambox as yourdomain.com or a subdomain, like team.yourdomain.com.

There are two steps for doing that:

1. Create a CNAME entry

Go to your domain panel and create a CNAME entry from whatever.yourdomain.com. to teambox.com. (notice the extra dot at the end).

2. Configure your organization

Edit your organization’s settings on Teambox and set the domain or subdomain you just configured right there.

And that’s it, you now browse to http://whatever.yourdomain.com and you should see your branded page, with your logotype and customized HTML if you filled that while editing the organization.