As a website owner (or webmaster/builder) you are of course curious if there are any improvements possible. One of the web tools you can use for these questions is Nibbler. When you visit http://nibbler.silktide.com/ you can enter a website. After this Nibbler will visit this website and calculate where there might be improvements possible. Nibbler wil check in the following categories: Accesibility, Experience, Marketing en Technology.
When you click on one of these categories you can see what test have been executed. The test is a link to the result, making it easier to find out what kind of improvements can be made.