Chrome: Google+ notifications appear on all Google sites, but if you find them distracting or wish you could turn them off, the BlockPlus add-on for Chrome will remove them from all sites except for Google+.
The add-on doesn't change anything about Google+ itself, but when you're visiting Gmail, Reader, or another Google site, the only things you'll see in the upper right are the settings gear and your profile. Nik Cubrilovic, the developer, wanted a way to use Google sites for work without being distracted by his latest Google+ responses. Do you find the notifications distracting or useful? Leave your thoughts in the comments.