"In December 2007, Reader linked up with Google Talk (the chat feature in Gmail) to display shared streams from friends. Within the context of feed reading, it fomented something of a Neolithic Revolution. Foragers, hitherto gathering headlines on a crude and solitary basis, became farmers, cultivating streams of information for their neighbors. Sharing increased 25% overnight." [1]

[1]: https://www.buzzfeed.com/robf4/googles-lost-social-network