Thank you PhoneOperator. Here are some additional questions..
>Our Platform connects calls directly to their destination, without the disruption of transcoding - calls are routed point-to-point, with low latency, without SBCs (Session Border Controllers). - See more at:
http://numberservice.com/#sthash.kC8YNi2G.dpuf1) So you bridging the calls with 3pcc?
>Record all your incoming and outgoing conversations and refer to them later - See more at:
http://numberservice.com/#sthash.kC8YNi2G.dpuf2a) is the media going thru your servers?
2b) How many simultaneous calls can it handle?
2c) Is the media going over private connection or internet? If over private connection, what is the cost to interconnect?
3) Do you have your own gateways or using a VoIP provider?
> I am using an enterprise grade voip provider.
4) How are you interconnected? Over Internet or private connection?
5) What number do you put in the 'calling party number' field on outgoing calls (SIP From, Contact, P-Asserted-Identity and Privacy Headers)?
6) If you integrate this service with, let's say NXTTY ;-), how do you provide privacy? Seems like you are using a gateway. How is the stream to gateway? Is it encrypted ? (SRTP?)
7) What protocols do you use ? SIP, RTP, SRTP?

Where do you buy your phone numbers from?
Like the speediness of the site :-). I think linking up with apps like NXTTY (assuming it will be successful) will probably help more. The UI on NXTTY will just provide the interface to your backend API code. I like the service that you provide. I am not sure how much you can charge for it to be profitable.
Sincerely
nr