Hi Brave, great question. I have always used my email via my Internet service (Century Link) provider so I can indeed block people. I was just reading an article the other day about Google and email privacy GMail privacy report
I think the issue with social media is that it all seems great until something goes wrong and you have no where to turn. That is why we don't use free/public software here because it would lead to exposure of emails etc.
I am not clear why people want the world to follow them on Facebook etc. I have a Facebook account under another name just because some sites that I visit will only allow you to post using a Facebook account. Personally I feel like I will be contact the people I wish to. If I am that close to you that I want to share pictures I am very capable of loading a slide show using Shutterfly.
I think the last years the public erosion of boundaries has really taken off. Maybe my age is showing, lol, but it just doesn't interest me to be chumming around with a bunch of people that the only real thing we may have in common is we own computers;)
I am not making these statements in any way to judge people who find that social media is their thing, it just isn't for me. Too many people over the years have come here from escaping from the Psychopath in their life they met online. Is it possible to meet great people, clearly it is but with that a person has to have the strength and will to weed out the whack jobs. I guess I just don't see myself dealing with it, life is complicated enough for me.
Does your Internet service provider include email service? I would think they would, and that would be where I would check. Perhaps some other people here can add what they have done to avoid this issue. I think in general all the free email services are set up that you can't expect any level of privacy.