No one can really guarantee much about pretty much any of that one way or another. Not really any more or less as to how all that applies to the other job boards that were mentioned before. Looking over the privacy policies of the services involved would be the closest that anything can come to touching upon that, but even those usually won't really say too much of anything actually definitive one way or another.
I did read the link provided earlier to LinkedIn's privacy statement.
Although it was written by lawyers, it seemed fairly straight-forward, and just based on that, I'd say it meets what I would expect.
But to be clear...
1.) If I upload my resume, and later I delete it, can I assume that it is gone for good? (As in, LinkedIn won't publish it later because they feel like it.)
2.) If I create a profile, and later decide to delete info in my profile, is it gone for good? (As in, LinkedIn won't publish it later because they feel like it.)
3.) If I "connect" with people, and later decide to "unfriend" them or whatever, is that gone for good? (As in, LinkedIn won't publish it later because they feel like it.)
4.) Is anything I publish to LinkedIn similar to tweeted, where the social media papparazi are waiting to screenshot your content the second you post it?
THIS is probably my biggest cause for caution...
If I upload my resume or update my profile or link to my former boss - who kept bugging me to do this! - and then I change this infomation or take it down, I don't want an Archive.org thing to happen where this information is "out in the wild" for life.
I mean from a practical standpoint, what if I update my resume and the old version had wrong/chanegd info? You wouldn't want outdated/incorrect info out on the Internet forever, right?
It was my impression that LinkedIn is more like Facebook and Twitter, where once you post content it is out there forever just as if you shouted it out ver a bullhorn or spray-painted it on a wall.
That is too much for me and my eprsonal life. (For my startup business, that is okay.)
Now, of course, all of the above questions are not asking what happens if tehre is some big data breach at LinkedIn, because then we're all screwed.
But I'll end with this...
In the early 2000s I joined some social websites where I later decided I wanted my profile taken down, and the owners refused. Ever sicne, I am very leery of running to create any profiles or post any pictres or resumes or whatever, because I have been burned before...