Next Door.com allows people to sign up and virtually meet their neighbors in a social, non-threatening way, and be able to share information such as an emergency alert, neighborhood event, or the ability to discuss community issues. I joined the group simply because I was invited, which is the way it grows. I suppose it will prove to be worthwhile, especially the aspect about discussing community issues because people tend to be more vocal online than in person, IMHO. One thing that amused me was a statement by the website people that said:
We believe in the traditional notion of neighbors as people who help and look out for each other. We hope that Nextdoor members embrace the concept of being neighborly to each other.I only hope that this is the not world we are becoming where people need to have a website help them watch out for each other rather than common courtesy and simply being human.