When discussing G+ it is best to regard it as an experiment. It is not the first social network venture from Google, it might not be the last, but this one is in trouble.
Early indications of strong uptake have faltered when scrutinised, the initial hype has faded, and strong campaigns earned Google respect as a brand but failed to drive users towards G+.
For businesses, especially small businesses, taking the time to build a public presence via Google+ alongside their Facebook and Twitter accounts can offer several benefits. The biggest lure for business is that Google prioritises G+ results when crawling the web, giving a boost to SEO.
But herein lays the problem; by focussing so well on how to bring business to G+, how to make it efficient for advertisers, profitable for brand pages, and hoped that the users would flock in behind this.
Interactions are low, activity is low, user numbers are comparatively low. G+ is the town they built down a dirt road when the motorway was already there. It could only have been a ghost town from the outset.