What else is the motivation of those behind this service, if not to easily harvest login information, files , email and and ip adresses of people uploading files via their service ?

Don’t get me wrong, a service like this could be very helpful,
but they have to do much better to convince me to use it.

Bandwidth costs money and a service like this needs lots and lots of bandwidth and therefore heaploads of money.
And we all know, people rarely upload private holiday videos to such file hosters.

To me this looks like a RIAA/MPAA/IFPI setup until proven otherwise.

“If something is too good to be true, it usually IS too good to be true.”