The number of active G+ accounts -- publicly posting in any given month -- is less than that. I and Eric Enge, he of Stone Temple Consulting, have independently estimated this based on G+ sitemap sampling. I pulled about 50k profiles off a single sitemap, Enge 500k from multiple. My pull was based on strong evidence that the profiles are randomly distributed through sitemaps. Both of us found ~6-12m publicly active profiles.

Among my thoughts: the group of people really discussing things online just isn't that big.

Reader was far more significant than Google realised.

https://www.stonetemple.com/real-numbers-for-the-activity-on...

Feedly probably isn't claiming those numbers with any basis in reality. In particular, many people made Feedly accounts in a hurry out of panic when the shutdown was announced. Having used both, I highly doubt users of Reader are still regular users of Feedly.

I always wonder what would be the active-user count for G++ without YouTube (i.e. every logged in Google user visiting a YouTube page is marked as an active G+ user if she scrolls down the page once).