Sometimes you want to quickly share a screenshot with someone. Here's my favorite mechanism, which assumes you have installed both curl and the ImageMagick suite.

$ import png:- | curl -T- -s

When you run this command, you cursor will change into crosshairs. Click on a window, and this will grab a png image of that window and send it to using curl.

You'll get back a URL that you can use to share the image with people.