At lifehacker I came across this incredible tool for del.icio.us. It is called the del.icio.us Direc.tor. It a combination of webapp and del.icio.us API and Ajax.

This probably is one of the steps were going to see on the web, web applications that are written over webbased apis. Web based tools with nice user friendly clean interfaces that do something that's different enough from the actual data provider website.

Very impressive. We need more of this.