Have you tried Mastodon yet? Well i suppose that's more micro blogging (ie. Twitter) replacement than Facebook. For something like Facebook there are Diaspora and Friendica among a few others.

Of course the problem has always been to tell your friends and acquaintances to switch... Resistance to change is always strong.

Did you know that there are also secure instant messengers and chats?

But why stop there?, Is your operating system secure?