I don't even know anymore. Seems like it is a wait-game for either something new to pop out that will awe the audience or for someone else to go out of business.
I remember when I bet a lot on Google Plus. I liked the platform and what Google was doing with their privacy customisation through a concept of circles. But apparently very few cared for that.
Regardless, I've heard different about Google Plus today. From a recent Fortune article dated just a month ago, "When Google joined the social networking space in 2011 with Google+, more than 25 million people joined in the first month. Now the number of true users on Google+ is less than 1% of the total 2.2 billion users on Google, according to a report by Stone Temple Consulting."
I think you have to look at it from a different perspective. You don't have to post on Pinterest or Facebook if your users are not there. Focus only on channels that make sense for your audience. It is different for any industry, but from what I noticed in web hosting, Twitter seems to be the most popular channels where people are present. Instagram is pretty much dead for web hosts, you won't find anyone. LinkedIn is definitely not dead as so many people are on it, but whether the engagement is down is another question. What I am certainly noticing is that people are getting less time to share in general.