What is a "vanity" website, for research?

A vanity URL is an unique web address that is branded for marketing purposes.

Vanity URLs are a type of custom URL that exists to help users remember and find a specific page of your website. Therefore your vanity URLs should be easy to remember, use, and share.There are many benefits to being the first to claim your vanity URL – and just as many setbacks if someone else beats you to it.

Many social media websites such as Facebook, LinkedIn, Twitter, and most recently, Google Plus offer users and brands the option to customize their gplus profile URLs.

Vanity URLs should not be confused with vanity domains, which are domains named after the owner’s name

It's for branding and marketing :) hope this helped