When you are reading a post on Google+ the page might contain the IMHO annoying banner to join Google’s social network. The banner distracts you from reading the article - it even follows you when you are scrolling. This bookmarklet for your browser’s toolbar hides the banner.
To use the bookmarklet, just drag and drop it onto the bookmarks toolbar:
Usage: When you are on a Google+ page that shows the banner, just click the bookmarklet and the banner should disappear. It will be displayed again after reloading the page.
Tested in Mac OS X 10.6.8: Google 19 beta, Firefox 13 beta