I am talking about sites like these::http://www.hegartyonadvertising.com/ http://activatedrinks.com/#/activate http://community.saucony.com/kinvara3/ http://www.freshtilledsoil.com/#welcome
You're thinking of a single page website. The general idea is to just keep everything inside a single HTML page which makes managing loading times, styles and content generally easy for low-content sites, with none of the "white flash" of navigating between different HTML pages in multiple requests. They're very popular lately for portfolios or simple business websites. They don't even have to be "long", and sometimes the anchored links take you to different visual pages, but generally the defining feature is a single html request. AJAX and simply hiding/showing different divs/parts of the page can prevent the "long vertical" aspect of these sites while maintaining a moderate amount of content.
They're a bit of a craze and have some fans like http://onepagelove.com/ which collects good examples.
Something that could be the same and could be different is the Single Page Application which is realistically only different in that "Application" tends to mean you can do something with it (like Gmail) while "website" tends to mean you see things but have less interaction with them (like a portfolio site).