yea but this is a very concentrated list of extremely private information - for your whole life, a list of people you were interested in hooking up with could cause all kinds of harm.
Not on average. As marciovm pointed out, this is highly concentrated. It's also the kind of information you might be unlikely to put in an email or IM.
Trusting people with email and credit card info carries legal and financial risks, but this carries a social risk that can have a much longer-lasting effect.
True. Which is why I'd think twice switching email providers.
Obviously you make a decision every time you give another entity any information, and storing data with Google/Facebook/et. al. carries risks as well.
But, as others have pointed out, the concentration and nature of this information matters too.
I'm reminded of the Veronica Mars episode about the "Purity Test" -
Step 1: get everyone's socially valuable data
Step 2: Hilarity/blackmail ensues
Just to be clear - I'm not accusing the site of doing anything nefarious, just pointing out the difficulty of establishing trust.
I suspect there's a lot of money to be made in figuring out how to bridge that trust gap (of course, that's a little bit like the various authentication or email trusted-sender schemes that float about - IF ONLY we could will some universally trusted and known-good structures into existence, certain problems would be that much easier to solve...)
