Thanks for +Daniel Treadwell‘s great work,finally we can easily add people to your circles en masse thanks to my newly created extension Circle+.
To use the extension, follow the link below and install it. Go to a page listing the profiles you would like to add to Google+ (sites like group.as and recommendedusers.com are great for this). Click on the circle in your title bar and choose the circle name you would like to add them to. Watch as the profiles are listed that have been successfully added.
Please keep in mind that limited testing has been done with this extension and there are plenty of signs that Google+ have limiters on how many people can be added within a given timeframe. Do not abuse this extension.