Any one currently working in or on Social Media platforms will know how time consuming it is to populate content, monitor engagement, answer direct messages and comments and generally manage each platform individually. It can virtually be a full time job for one client across the key 6 or 7 platforms.
Therefore is can be more than tempting to link certain platforms so that you effectively cross populate the content from just one platform or use a Social Media stream platform like Tweetdeck or Hootsuite that can manage multiple platforms from one hub.
There is definitely a place for these hubs and linking platforms but don't fall into the trap of posting the same content across multi-platforms and thinking that it is job done. That lazy practice and you will likely see a quick decline in engagement. The reason being that each platform needs individual management to gain the best results. For example, The requirements needed to manage content on Facebook is vastly different from the content requirements for Google+ which again is different from Twitter.
It all comes down to the little details and unless you take the time and trouble to go into each platform, you will never fully utilise the platform's full potential and ultimately deliver a ROI.