Here's a brief: Instead of tweeting to one server, you tweet to many. When you and another person share the same server, they see you. Those servers (relays) can also be broadcasting your messages to other relays, so you might end up indirectly sharing servers as well. Because there are so many servers that potentially sync data, it is supposed to be "uncensorable". Each user is identified by a public key, and signs their message with a private key.
As for the SN aspect; you follow people. Hence the Twitter comparison.
Now what I did not mention on purpose: You can do microtransactions in bitcoins. And if you read that and thought "oh god no" - then yeah, exactly. xD
Let's see... Just today, in their presentation for the next patch, a child character got a new outfit, and a teaser that the next archon (god) is a kid - again. xD
I sometimes wonder wtf they're doing, ngl...