What Annoyed Me Today . com
It was more like a social experiment but became very successful with a very little advertisement. However, poorly done backup and a harddisk crash caused most of the annoyances posted here to get lost. Though their copies still exist on Twitter and Facebook pages.
The goal was to find out what annoys people around the globe, and it was very interesting to see how these annoyances factors vary across the globe. For example, in the UK, most of the annoyances are due to boyfriends or girlfriends trashing each other, whereas in the USA people have mostly work related annoyances.