Google+ ID is the id which Google+ has uniquely assigned to each user. To get your Google+ profile id click your name on your profile page and then copy the 21 digit number as shown in the picture below .
Here you will find groups of people that you may wish to follow on Google+. To add a Google+ user please enter their Profile ID or URL in the text box below, choose a group, and submit!
Go to your Google+ profile and copy the long number from the URL into the field above.
Disclaimer: Alpha version, script may be broken at times as I change stuff...
Known API issues: only a maximum 250 posts can be retrieved / the API sometimes returns an error for users with lots of activity (sorry Robert and Tom) / for some people the API client throws an "invalid json in service response" error
If you have questions/suggestions/problems or want to stay updated on changes you can circle me on Google+.
The ripple diagram shows this post spreading as users share it on Google+. Arrows indicate the direction of resharing. (Only public posts show up.) Circles within circles represent a resharing sequence, so large circles indicate heavy resharing.