Idealizing a Social Media System

In Robert Gehl's reading Reverse Engineering for Social Media, the author explains four interesting arguments related to idealizing social media system. Gehl explains that the most obvious required feature is the equal capacity to receive and transmit for networked computers. Next, he explains an idealized social media system must be platform independent, that it must run anywhere, whether on rebuilt computers, or jailbroken phones. Socialized media not only should be platform independent and open source but also should run on free hardware. The last point he mentions is having an "Decentralized architecture". We all know that a dominant social media like Facebook is a centralized architecture system, but what do you think Gehl means by social media system having a "decentralized architecture"?