A global VOIP service that is based on open standards. Or an open social network, also based on open standards. Both should be extensible.
Is SIP [1] not open?
[1] https://en.wikipedia.org/wiki/Session_Initiation_Protocol
Imagine what would happen if we had the same issues with our phone lines. The last real open service we created as a humanity is email. At least SMTP still works.