Working Against It
Google+ is up against the same acquisition and retention issues every new social platform has -- people are already on the networks they're on, and as of yet, there's no extremely novel reason to post your photos and updates to Google+ instead of Facebook or Twitter. Plus, you can't import your friends or data from other services (yet), meaning you have to rebuild your network from scratch. You could cobble together most of the features from services you already use.
Moreover, the user experience has a learning curve: it seems to expect that you've picked up tricks from other services, but also modifies those actions slightly, so you have to "re-learn" some of the basic functions. For someone who's only used Facebook, the follow/following mechanism is harder to grasp. And a few obvious features -- like integration with Google Reader -- are missing, and feel like holes.
In Its Favor
What Google+ has going for it is transparency and versatility. Not only is it easy to customize sharing settings via Circles for every piece of content users post, Google also makes it clear that users maintain the rights to all their content posted to the service.
The other real advantage is how flexible the service is. While you could get access to most of the features through other platforms, Google+ has done the best job of combining status updates and photo sharing, with services that have yet to become truly mainstream: check-ins, group messaging, and group video chatting. Now it's all accessible in one slick interface (the desktop-to-mobile experience is nearly seamless) and one list of contacts -- no more pleading with your friends to download GroupMe or leaving non-iPhone users isolated without Instagram.
Brands Can't Wait to Get On -- And That's a Good Thing
Google has been transparent that it will offer differentiated brand profiles from those for individuals. It's promising that brands won't have to fight for support on the service, since their investment (creative and financial) will make it cooler for consumer use. Deep integration with other Google services, both content-hosting platforms like YouTube and advertising services, will make it a compelling creative development and data mining opportunity. Hangouts, maps, check-ins and more will enhance the types of information they can share and help merge brand and business resources for fans. From the looks of things, brands will love Google+.
Ultimately, Google+ will find success among people who have diversified social networks (professionally, geographically, or interest-based) and who customize what they share with those social circles. It's also going to hinge on what gets shared back from other friends, but also from other content creators like brands, media outlets, musicians, and more. The best part about Google+ isn't that it's an information platform or that it's a content platform -- it's that it's both.
Whether Google can sufficiently diversify and differentiate its services and content to scale out beyond their beta testers and early adopters has yet to be seen, but the pieces are in place for success: a varied repertoire of services, simple yet fluid management of contacts and content, and both individuals and brands clamoring to contribute. Your mom may feel that Facebook is sufficient for keeping up with friends, but for those of us who live and work more fully online, Google+ is a compelling offer.