Whether Facebook or Τwitter are secure or not... where is the expectation that they be totally secure? What is on there that needs securing? I have a disposable email address (on GMail) I use for anything like that, and I use different passwords and logins for sites that I do require to be secure. I don't use Facebook or similar services, because I know they gather information for the purposes of marketing stuff to me, and I don't make a good target market for advertising. I understand why people are concerned about those.
I do use Τwitter because it's fun: I expect little from it, and it asks little from me. They have (so far) shown no signs of trying to gather marketable information from me, but I know that they're a business, and will need to make money some day. If that happens in an intrusive way, I can just walk away. I look at some of those "Luddite" comments, and fail to see how they can be applied to Τwitter at this time.