Nomorobo was one of the three 2013 winners of the FTC Robocall Challenge. According to PC magazine's 2015 review of the site, it's the only winner that has a service up and running on the web, and it's FREE! It does not work for cell phones or for analog landline services. But for all other landline services, it works. Supposedly. Hey, it it did for me -- instantly! I signed up yesterday, and I've gone from 10 robocalls a day (minimum) to zero. I hear one brief ring and then blessed silence. It's a MIRACLE! And this just in time for onslaught of political robocalls that were about to crash down on my peace of mind like an avalanche. I am SO THRILLED!
For a more technical POV, here is an excerpt from that Sept. 2015 PC Magazine review:
"The good news is that Nomorobo is free, easy to sign up with, and works as promised. I used to get at least one or two robocalls per day. The only sign of them now is that the phone rings once. If I'm curious, I can go to my Verizon FiOS account online, see the calling number, and search for it in a browser. So far, every blocked call has been from a known robocaller, with the number also showing up in my online searches on assorted sites that track annoying calls.
The bad news is that you may not be able to take advantage of Nomorobo. Ideally, it should be directly integrated into the carrier's internal call processing, which is what Ooma Premier and Sonic do. And in principle, it should be able to work with any carrier. All it requires is that the carrier support simultaneous ring, so incoming calls can ring both your line and Nomorobo's line at the same time. In practice, unfortunately, that feature is currently available only on VoIP carriers, and not even all of those.
The list of carriers that work with Nomorobo has some significant players on it, including Verizon FiOS, Comcast Xfinity, Time Warner Cable, and AT&T U-verse. (You can find the full list on the Nomorobo signup page.) Missing, however, are all wireless carriers and all analog carriers. So although it works with Verizon FiOS, it won't work with Verizon Wireless or standard Verizona plain old telephone service (POTS) line to those who follow such things."
It took me a bit of work to sign up on Nomorobo.com. I had to sign into my Verizon account (find the online ID, password, blah blah) and then follow the steps the site listed. But was it worth it! I just can't understand why I haven't heard about this service before. I guess the truth is it's free, which means not much revenue, which means no advertising. I suppose they have grants or government funding perhaps? In any case, I wish I'd know about this site sooner -- it is WONDERFUL!