Floobits - Floobits brings real-time collaborative editing to text editors, IDEs, and now Atom.
GitDuck - GitDuck is the easiest way to explain your code to other developers. Show how you code and record videos linked to your source code.
GitLive - Extend Git with real-time collaborative superpowers
Keyory - Schedule periodic emails and get aggregated responses delivered right to your inbox with Keyory.
CodeTogether - Live share IDEs and coding sessions. See changes in real time.
One Degree - The Human Search Engine