The fat footer design trend started in early 2008 and seems to be ruling the 2009. Fat footer are very handy for giving users context within your site, offering another set of navigation to users or just for deep-linking for SEO gains.
Few benefits of fat footer designs are

You can use this as a sitemap [...]

A user will fill up the registration page of a site when he/she wants to access parts of a site or application. This is a long time challenge to design a form which convince user to fill-up all details.
Few basic things before some good examples:
1. Keep the registration form simple and if possible  max to [...]