There is no privacy when posting something to the internet.
By default, this is the only privacy strategy which makes sense anywhere on the internet, for the average user of large scale services.
Whenever you post anything, anywhere, but particularly on any kind of public forum or social network, assume it'll be seen by your current and future coworkers and grandmother. Assume it'll be the post/photo/video used to identify you on the news if you're ever in the news for anything.
If it's still ok, post away. If it's not, consider why you're sharing it on a social network anyway, and if it's still important to share with a select group of people, then consider sharing it by some other means.
I didn't down vote it, but...
Not everyone is technologically savvy. Snapchat became popular because of the implication that the pictures you take with it are ephemeral and private. It's sort of the whole point, isn't it? If not, how is it different than a SMS picture message?
Sure, to those who understand the tech, it's pretty obvious that whatever is sent through the pipes is out there, in perpetuity. But most people don't think like that, and Snapchat played on that misconception as a model.
It's not just Snapchat. Lots of software targeted towards programmers, sysadmins and power users relies on similar smoke-and-mirrors branding that tries to hide as much technical details as possible in favor of presenting grand high-level summaries that present it as a solution to an imminent problem. Either way, the assumption is you won't screen them.
> Why is this downvoted?
I agree with it, but that sentence doesn't add anything interesting to the discussion of this article. It also has a pretty decent chance of starting an even less interesting sequence of "no, I disagree," "no, I agree," "no, I disagree,"... replies.
The problem with publicly assuming the cynical position as a response to news like these is that, perversely, it removes any disincentives to actually doing it.