Google has announced via a blog post a number of improvements which should make Google+ easier to use and (I would imagine that Google hopes) more attractive to new users and 'sticky' for existing ones.
One of the huge advantages Google+ has had from the start is integration with other Google products - most notably gmail, although being able to advertise on the Google home page as they did when Google+ came out is also a huge (dare I say it?) plus.
Notifications about things happening in Google+ appear in a header bar gmail, and Google has now made this easier to navigate, introducing more content in a dropdown panel when you click the notification icon.
Google has also extended Google+ into the business world, and there is a specific way to advertise your business on Google+, using a "Google+ Page".
Finally a better photo lightbox has been unveiled, replacing the very klunky 1.0 version which, to be honest, looked like a rushed product.
So who knows, maybe in 2012 we'll all be Google+ing each other?