importlib: what is it, and why is it important?

[excord80]

Regarding this blog post: http://sayspy.blogspot.com/2009/01/importlib-is-now-in-python-31.html

When I use the ``import foo`` statement at the top of my program, I
get a module imported. python has a search path it follows, finds the
module, and makes it available to my program. Works nice. :)

So, could someone explain what importlib exactly is, and why this new
version that will be in Python 3.1 is significant? Will the import
statement work differently in 3.1, and if so, in what way?