Privacy is awesome - one of the few services I highly recommend to anyone who makes purchases or pays bills online. Slick interface, product just works (except once when I pre-ordered something from Best Buy and that's because Best Buy had a very weird authorization flow that did two charges, instead of an auth + charge) -- and the benefits are great. Best of all, merchants cover the costs, so it's totally free as a consumer (edit: meaning, no monthly fees, etc -- of course merchants have to cover their card processing costs still). Their support is great, too.
I do wish their referral or spending perks were a little more enticing but the privacy benefits are still great overall.
Will be thinking about how I can effectively use the API...
EDIT: Woah, this is REALLY cool:
> Similar to the transaction event, auth stream decisioning will allow your system to dynamically approve and decline authorizations.
https://developer.privacy.com/docs#auth-stream
I smell a two-factor purchase flow in my future... (edit again: maybe not)