How to: add features to Firefox with Mozilla's new Jetpack

For someone who has played with this, is the DOM manipulating similar (or more/less powerful) to Greasemonkey?

Jetpack is cool, really cool. All browsers should allow plain javascript/html web extensions. I hope it gets standardized by the W3C in the future.

What I don't like is web pages asking me to install them when I visit them.

There should be just a link to the extension, like old xpi. A link, not a popup. If you want, you can use JSX as the entension and instruct the browser to behave accordingly.

Mozilla, please get rid of the extension installer pop up and the {link rel="jetpack" href="myextension.js"} non-standard aberration.