I recall reading almost three years ago about a pair of Google engineers who won a prize in the FTC's Robocall Challenge, but at the time weren't pursuing it further. I wonder if that is what's powering Fiber Phone's spam filtering?

I have a free Ooma landline, which isn't tied to a specific ISP, but if someone can truly crack the problem of call spam, I could definitely see that being a valuable service many would be willing to switch and pay for.