[77544cec]

Collaborative filtering is better than law IMO.

My phone company shipped a phone app in the app-stores that you're supposed to use in replacement of the default phone app. It comes equipped with collaborative filtering to weed out robocalls: when one rings your phone, the phone app displays it as such as well as the number of people who have reported it.

I used to have one robocall a day, but not anymore. It looks like this simple technology has made robocallers give up.

[viraptor]

This is not an effective system. Caller IDs are often not verified in any way. Unless the scam/robocall requires a callback, the number will be made up. Collaborative filtering can't solve this.

[77544cec]

It did in my country (where you can't make up a phone number).