"If there is an open source social platform - it’s Twitter. There are a minimum set of rules other then the 140 character messaging limitation. There are no limits on who and how often you message folks who follow you. All the apps built on Twitter are by default open - as all tweeted items are in the public Twitter domain. Thus all commands, messages, actions, reactions cause Twitter to look and feel like a public command line."

Todd Sawicki, Twitter the Open Source Social Platform