I have Sync.Net installed on my phone. It has an option for automatically declining calls from numbers that have been flagged by other users. Disclaimer: it's

I have Sync.Net installed on my phone. It has an option for automatically declining calls from numbers that have been flagged by other users. Disclaimer: it's very sketchy because it takes your contact list and uses it for other users in the reverse lookup feature. Which is a neat feature, you get FB picture and name of the caller on each call, but still a privacy concern.