What of sites that unilaterally change rules retroactively? Or fail to provide reasonable alternatives?
Facebook does all of the above.
To an extent that I don't trust it, and don't use it.
But there are plenty of other services which wave the "but you consented!" flag. Google comes to mind, and I've had my set of issues with them as well.
And when you're browsing a web site with a Facebook Like button (that you don't click on), you're giving information about your browsing habits to Facebook and it's totally non-obvious.
If the button image is hosted on Facebook's servers (and it commonly is), they have a log of your request for it, including the page it was on (from the "Referer" header). This request is sent when you load the page, without the need to click on the button. Every site you visit that includes a Facebook resource gives them the ability to collect data about you and your habits. These are often part of a site's template, included without regard to the page it might appear on. You'd be surprised what a Referer URL can reveal about you.
What of sites that unilaterally change rules retroactively? Or fail to provide reasonable alternatives?
Facebook does all of the above.
To an extent that I don't trust it, and don't use it.
But there are plenty of other services which wave the "but you consented!" flag. Google comes to mind, and I've had my set of issues with them as well.