Zeus Kerravala, an analyst with ZK Research, said it could be that Google, by ending its mandate that Gmail users sign up for Google+, is backing away from its social network or it could be that the network is growing enough without forcing people to join it.
"Now that users don't have to sign up, we should have a better idea as to whether users are signing up on Google+ because they want to or because they had to. We may see a precipitous drop off in Google+ now."
If the company isn't talking about the Google+ user base, however, it will be hard to discern what is happening to it.
"It's an interesting move," said Kerravala of the sign-up mandate change. "I think they're just letting users decide whether they want to be part of that community. It's still the second largest social network."
Google also simply could be letting Google+ move away from its role as a social network - and Facebook rival -- and into a role where it serves more as an integrator for various Google products.
While it's a social network, Google+ also has been a tool that CEO Larry Page has said he wants to use to integrate the company's different services -- from Gmail to its cloud-based office suite, Google Apps.
Integrating Google+ into other Google services would effectively embed identity and sharing into all of the company's products, transforming the Google experience and providing information on what its users want, when they want it.
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