Wildcard - Discover, connect and meet people at communities
Boomerang Respondable - Write perfect emails with Artificial Intelligence
Shapr - A completely free way to build your professional network.
Mailbutler - Mailbutler adds lacking functionality to email clients and increases your productivity
LetsLunch - Do more with your lunch hour. Meet new people.
Boomerang for Gmail - Boomerang for Gmail is a Firefox / Chrome plugin that lets you take control of when you send and receive email messages.