6M users is just not interesting when you're chasing having hundreds of millions of users. And 50% is a wildly optimistic percentage for how additional G+ users you'd create.

Let's say they have 12M monthly active users; a large percentage of those are probably already G+ users (let's call it 50%.) A large percentage of the remainder have deliberately decided they don't want to use G+, so you'd be doing pretty damn well to convert 10-20% of them over.

So that's only 600K-1.2M MAU in a "best case" outcome. You're just not going to be able to sell that as being worth allocating a half-dozen engineers to pursue building a new product. It's not even close.

The last 6 million maybe nothing, but the first 6 million is huge. So is the 2nd and 3rd.

>6M users is just not interesting when you're chasing having hundreds of millions of users.

In the use case of a type of site where cascading network effects are of paramount importance, 6M engaged users is huge.

Yeah, but you're assuming they'd be engaged. If they don't like G+ and they're just using it as a news reader, that's pretty much the opposite of engaged, from a social network perspective.

> My understanding was that Google Reader had somewhere around 12 million users.

My understanding is that the better figures are closer to twice that: http://www.gwern.net/Google%20shutdowns#fn5 (and that Reader users were very active).