You're browsing the web and you click a link to an article on a site (let's say nytimes.com) but instead of getting the article you get a screen asking you to login or register. Infuriated at the idea of pointlessly registering for yet another site you turn to your good buddy bugmenot.com
Here in this site you can get a user ids and passwords for any site. Hence we dont need to register for any site which you think you're not going to use again.
Here is the link