From February 27th, 2014 to September 24th, 2014, 50% user give 5-star rating, 50% user give 3-star rating. for GitHub +1 chrome extension.
I thought this would +1 the page with Google+, but instead, it posts a comment on the issue that says "+1". I don't like this method, because it's spammy.
What a fantastic little extension!