**Deprecated and will be removed after September 30th, 2016**
A social activity represents a social action (e.g. +1, comment, vote, share, etc.) that references content on your website but does not originate from your website. Instead, the social action originates off-site, on a social network.
So, if somebody post a comment on your content that has been shared by somebody on Google +, you will receive a notification in Google Analytics.
Social activities also include additional metadata related to the action, such as: the social network, user, time, photo, comments, etc.
Google Analytics will display the following information for you:
And you can find this report here: