I've been using this site for years, but I guess there are still a lot of folks that don't know about it.
There are a lot of websites around that provide free content but still require a username and password to access that content. I suppose they want to do this so they can generate more accurate data on visitors to their site. It's a fair and modest demand for a site that's providing valuable info, and I have accounts at many of these types of sites.
But when I click on a link for a site that I've never visited and am unlikely ever to visit again and am prompted for a username and password to view a single bit of content, that's just annoying.
So I go to Bugmenot.com, enter the website that I'm trying to visit and usually get a list of usernames and passwords what will give me access to the content I'm trying to view.
the New York Times is a good example of this type of site. A lot of news services (such as Google News provide story summaries from sites like the Times, but when you try to read the actual article, you're required to have an account. Bugmenot lets you get at this content without having to generate dozens of website accounts that you'll likely only use once.