Situations like these do arise, it is only with great care and some sacrifice you get to walk this path. Losing out on the discourse between those who use different messenger protocols or who communicate through the likes of Facebook or G+ is one of those sacrifices. You can try to convince them to join you on some other channel but the chance of this succeeding depends on those friends' attitude towards both the subject of personal privacy as well as your reputation - if you cry 'wolf' at every opportunity they'll soon consider you to be a tin-foil-hat wearing loonie.
Fortunately the evidence against just those actors - Facebook, Google and others - is getting more and more visible and palpable to all. Between Facebook's blatant censorship of content and Youtube 'demonitising' [1] 'controversial' videos and actors, it is getting hard to avoid noticing that they are flexing their opinion-influencing muscles. This should make it a bit easier to convince people to jump ship [2] but you won't get all of those people to forego on the delights of Spies'r'Us or CatVideoCentral. Still, once a few of them join you you'll no longer be out of the loop and that is what matters here.
[1] a good word in this context as it almost reads as 'demonising'
[1] ...and please tell them that moving from Facebook to VKontakte is not an effective move in this respect
If some pass laws that make my choice to go outside FBook, Google or whatever-Internet-monster, then I'm screwed.
That my current nightmare. But I have not the faintest idea if this is close to reality or not. EFF zealots would probably very close while the very existence of ubiquitous free software says the opposite. Dunno...
Well, I don't think, there will be a law soon that requires an FB account or alike. But there have been cases, that people had to show their FB account at the border, or need it for school/University (or for job interviews )- so if there will be a structural disadvantage for people out if the corporate chain, then it will be a de facto law.
let's say your friends are using WhatsApp, or Skype, via proprietary protocol, but you only use open sourced IM, then you are isolated from them.