Google+ has come a long way since its beta days only a few years ago. The intention of Google+ wasn't very clear to the public, as most saw it as a jump into an arena that was receiving huge attention elsewhere in the form of Facebook and Twitter. This of course was never Google's intention.
Google+ was intended to be a premium service to your current Google account services. It was necessary to require a second sign up for these services, as Google+ was about real identity online, and pushing services through this real identity. Google clarified on a few occasions, one such occasion indicated that it was a social layer that enhanced many of its online properties, not simply a social networking website, but also an authorship tool that associated web-content directly with its owner / author.
"a social layer that enhanced many of its online properties, not simply a social networking website"
Google+, at its core, had the social networking aspect, but would grow to include further services that spoke to the core of identity use and shared content. The introduction of Google+ sign-in across the web, made use of your identity within Google+ to sign up for other online web services and apps. The extension of the photos section into a more robust photo management suite (including auto uploads and auto editing) was a huge pro for drawing in users for photo management, and sharing of those photos. Hangouts was then introduced as a chat service that leveraged off photo storage allocation of Google+ (without a Google+ account, you could not share pictures in hangouts).
So Google+ started out with the intention of PLUS'ing a typical Google account to produce more real identity engagement experiences online, however users purely associated Google+ with social networking, and competition to Facebook. Many people refused to sign up for yet another Social Networking experience, and so also were left out of the full experiences of hangouts, and Google+ photos.
A lot of rumour has recently arisen speculating about the end of Google+ (less likely), and the splitting of services from the Google+ brand. If you ask me, it makes a lot of sense to open up features such as hangouts and photos to all regardless of whether they have a Google+ account or not.
So, if Google opens up Hangouts and Photos to the general Google account users, this means that all that is left within the Google+ bubble is the sharing of pictures, videos, location, links, events and thoughts, which makes the remnants a more direct Facebook competitor. It also means that Google+ is no longer really a plus or premium Google experience, but rather a purely social networking experience, and maybe a name change is in order ... cough cough ... Google Link, Google Connect, Google Social, well something in that arena.
With Google Photos being a stand alone service, services that require photo storage location would then feed in and out of this service. With a standard Google account, you would be able to:
- Store photos in Google Photos directly (auto uploads etc),
- Engage in Hangouts without a Google+ account, as your Hangouts pics would link to Photos, which don't require a Google+ account,
- And if you do have a Google+ account, your sharing would store to Google Photos too.
The above storage model would still be in line with Google's Storage plans that share storage across Gmail, Google Drive and Photos.
