Interesting article on the Caller-id. I suspect the telcos learned how to maintain a CLID database from the Realtor;s MLS.
My point is Ooma does the lookup (for premium users) at the time of the incoming call. It's then displayed on my Caller-id device and stored in the call log. If that person then leaves a voice-mail, I think it should be stored there as well. That shouldn't involve another database dip.
On the FB lookup, I don't know how it works and I have never coded FB apps, but I have coded other online lookup apps. My guess is Ooma doesn't store the data but Ooma app queries a FB app that has been given permission to access your account. That's the method used by the Android FB app, and other web site links. If they didn't do it that way, they would need to scan frequently for changes, plus it may be against FB rules (speculation on my part).
Want a wakeup call? Try
http://mypermissions.org/ to see what apps you've given access to your account(s). I don't know exactly what these apps and FB collect, but I'm pretty sure more than I want them to have.
Robert