"Has your user script “outgrown” Greasemonkey's architecture? Does your user script need access to privileged Javascript functions, local files, or other Firefox features that are only available to full-fledged browser extensions? You can turn your user script into a full-fledged XPI with just a few clicks, thanks to Adrian Holovaty's amazing Greasemonkey compiler!"
- Mike Chelen
from Bookmarklet