I work for an ISP and believe deeply in online privacy. I've had the idea of offering up an as-private-as-I-can-make-it VPN service a few times, but I always end up at the same point: wondering how I could
prove that the service wasn't doing anything malicious or nefarious -- "taps", Netflow data, etc. would all be easily available to me.
What would it take to convince you that a VPN service was trustworthy?