Google has made a couple of changes involving the +1 buttons. The first in an aesthetic change that will change the button’s color scheme to red and white, while the other gives you the option to thank other Google+ users for +1’ing web pages.
Red Google +1 Button
The +1 Button color scheme is changing to white and red shortly. Currently, the buttons are mainly white before you +1 a page, and then mainly blue after you’ve clicked.
Say Thank You on Google+
Signed-in Google users can now thank others for hitting the +1 button. On Google’s personalized search results pages, you may now see the option to “Thank” somebody who is in your Circles.