What it does
1. Multi-column layout: Moves multimedia to the right half, and leaves everything else on the left half. Super-wide screens get more than two columns.
2. Make 'What's new?' box for you to enter posts, and make your Circles always available – they are at the bottom of the screen and don't scroll.
3. Remove annoying suggestions.
4. Vertical space saver: move the +1 statistics to the lower right corner of the post (either overlapping the picture, or in the bottom of the article preview text) Condense white space considerably.
5. Remove speech bubbles: There's an option to turn them back on. I personally detest them.
Link to Chrome plugin, in case you are interested: https://docs.google.com/open?id=0B52D6ns6sCFveF9vMEt2azdRR0k