"Firefox has been successful in large part thanks to
its rich ecosystem of add-ons. But writing add-ons isn't trivial.
That hasn't stopped development: Firefox has thousands of add-ons,
many that are immensely popular. However, it's far from trivial to
develop your own extension, and the Mozilla folks are looking to
make it possible for anyone who can create Web pages to create
add-ons.
"The bar for participation thus lowered, let's check out Jetpack
and see what kind of options it offers."