Google+ is a great platform for building communities, which is the core of a strong social media strategy. The fact that it is highly curated and moderated differentiates it from the other platforms out there. I would run special campaigns on Google+ and promote them on our other social media outlets to encourage people not familiar with the platform to become part of our community. Since posts on Google+ often rank higher on Google than regular blog posts or landing pages, it is a great SEO tool to attract new qualified leads.