I think if Google felt it was a failure they would shut it down like they do with their other products.
What's Google + ?
Guys,
Google Plus now has 450 million + users
It is about to cross the total userbase of twitter
Plus, if a post is shared on g+, it gets indexed faster
and if you know about google authorship, it requires use of g+ if 'you want your photograph to be shown along with your site ' in search results
The number of people +1ing a site have increased tremendously...
It does have marketers as well as non marketers
Its very much alive !!