Google Reader added an option to increase/decrease font size for all the posts: press = to magnify text and - to decrease its size. Unfortunately, Google Reader doesn't save your preference, so the next time you open it you'll see the original font size.
While most browsers include a zoom feature (Opera, IE7, Firefox 3) or an option to increase the font size, Google Reader applies the new font size only to the posts, not to the entire page.
There's also a new keyboard shortcut for sharing posts and adding notes: Shift+D. To see a list of all the shortcuts, press ? in Google Reader.
Oh, and one more thing: you can now delete notes, not just unshare them.