I think the provision of powerful APIs (but with terms of use that say they can use any data that you gather with them) is a smart way of collecting a large amo

I think the provision of powerful APIs (but with terms of use that say they can use any data that you gather with them) is a smart way of collecting a large amount of this type of information. However, it's also not hugely clear (well, it wasn't when I was investigating using them a couple of years ago) when signing up to get access that that is what's happening. I was checking the TOU and noticed some alarming wording - basically, any users who used the Rapleaf API to upload their address book to my site, would also be giving their entire address book to Rapleaf (to do as they see fit). In the end, I used Octazen (later acquired by Facebook) instead.