1. Move your cursor to the dead center of your screen.
2. Hover your cursor over the Battle.net icon at the top center.
3. Move your mouse to the left.
4. Once your cursor changes from an arrow to a hand, click on it.
5. Welcome to "Create/Manage your World of Warcraft account" web page.

Thank you for your post Tom!

I must point out that this is no Easter egg... it's only a bug. The link is slightly shifted to the left, yes, but it's correctly linking to the "Create or Manage a Battle.Net account".

Anyway, I forwarded this bug report to the dedicated team!