Those icons don't strike me as being applicable to public information sharing sites like stackoverflow.com, gamedev.net, or any number of other sites. If you look carefully at these privacy icons, they seem to be primarily targeted at email service providers (e.g. Gmail, Hotmail) and cloud hosting services like Dropbox or iCloud.
Let's look at some of the icons.
Let's consider a few nightmare scenarios.
Say you're working on a novel and it's hosted in cloud hosting service X. Oh, your novel comes out a week early, under someone else's name. Oh, you find out. cloud hosting service X allows Your data to be used for purposes You Do Not Intend, and Your data has been bartered or sold. You have no rights, because cloud hosting service X owns your data, apparently.
Or another company releases the source to your top selling app. Oh, you find out. Your private online source code repository was not so private after all.
These are extreme cases. They probably never happen.
My point is, a public information sharing site should not have the same expectation of privacy that a private information repository should have.