You come across substantial news or blog articles that you want to read, but don’t have time at the moment.
You need something to read while sitting on a bus, waiting in a line, or bored in front of a computer.
Instapaper has a very simple design; you don’t even need a password or email address to use it. When logged into Instapaper, your links are sorted into three groups: Unread, Recently Read, and Recently Skipped. Buttons on the side help you sort links between the groups. Clicking one of the ‘Unread’ links automatically pushes a site down into the ‘Recently Read’ feature.
Instapaper also plays nice with the iPhone, featuring an optimized interface and the now-obligatory customized web clip.