I've just learned about the coolest web app - YubNub. I read about it in Roy Osherove's blog.
What it does is, it gives you a "command-line interface" to the web by allowing you to type in simple commands and then transfering you to corresponsing URLs.
For example, to browse an entry in WikiPedia, I usually type-in to my FireFox: http://en.wikipedia.org/wiki/X where X is the entry I'm looking for. In YubNub all I have to do is type-in wiki X and whammo! I'm there.
YubNub has tons more of useful commands that users added to it, there's a command to list them and search through them (the command is 'ls' of course :) ). Anyone can add new commands pretty easily. In addition, it's available as a FireFox search plugin (which I've installed ASAP).
And in a counter-revolutionary sort of way, there's a YubNub command that does "anti-YubNub". The command 'gui' accepts another YubNub command as its argument and gives you a GUI for inputting arguments into that command. Tres cool.
Now all we need is a batch language that can harvest the output from YubNub commands and funnel it to others we'd have the easiest framework ever for making mashups. Anyone up for it? :D