i provide an answer here in six basic points that cover architecture and information flow consequences for resiliency, autonomy, and privacy, as well as important aspects of the user experience, user compensation and the attention economy.
TL;DR: you are the network, not the product.
1) A distributed, decentralized architecture is more resilient against certain kinds of attacks. From a hacker hacking a centralized service and scooping up all the credit card data from a single database to a government shutting down a service providing information counter to the incumbent narrative, a distributed, decentralized architecture is more resilient against these kinds of attacks. Clearly, this is not the architecture that Facebook enjoys or promotes. It can't because its revenue model wouldn't work well in this setting.
2) Above this architecture, Synereo provides a qualitative notion of identity. This is not about identity as token because that notion of identity doesn't serve individuals who have rich internal multifaceted presence. What is needed is to be able to reveal enough about oneself to participate legitimately in a conversation without necessarily revealing information that is either sensitive or irrelevant. Consider a self-governance or participatory democracy process like the budget games. Were these conducted in an online situation people might be less likely to participate if the games revealed information about their political views that made them the target of unwanted attention. In the US such issues have included healthcare reform and gay marriage. On the other hand, a government representative needs assurances that the online participants are actually registered voters in their districts and not bots. Synereo allows users to reveal enough identity-related information to participate in a variety of processes without necessarily provding personally identifiable information. If someone is pursuing employment from an employer that is ok with them working remotely, then the employment application process doesn't have to reveal the candidates' residential address. Again, this approach doesn't fit with Facebook's revenue model.
3) Synereo makes strong guarantees about never letting Synereo code see user data in the clear (unless users' give explicit permission). Despite these guarantees, Synereo provides a sophisticated search mechanism that allows users to search content throughout the slice of the network visible to them. Facebook just rolled out a graph search. Many people are very concerned about what this means about privacy. If you would like to know more about how Synereo achieves this, awesome! Please contact me and i will personally explain the mechanism in as much detail as you would like. Beyond this Synereo is based on a mathematical model of decentralized and distributed computing that allows for the specification and enforcement of information flow policies. The language for these policies is exceedingly rich -- considerably richer than friends, friends-of-friends, etc. These policies can be autonomously developed and assembled into larger policies. The polices can be checked for desirable properties. This provides the basis for smart contracts that allows for just-in-time assembling of services from subcontractors. In other words, Synereo can help groups assemble temporarily to form an organization to complete a task or provide a service. This level of sophistication just doesn't exist in Facebook. It doesn't even exist in Ethereum. The Synereo white paper describes an example of information flow policies as relates to public health and public safety. We believe Synereo's feature set makes it an ideal mechanism for participatory self-governance.
4) Synereo provides the attention economy model. This allows participants in the network to begin to get some of the reward for their participation. It's not just that the monetization of attention deployed in social networks is commonly estimated in the 10's of billions of USD. Nor that Facebook users never see a penny of that. It's also that as a result of the shift in distribution mechanism the creative classes are under unbearable pressure. When a guitarist of the stature of David Torn gets 8USD from Pandora for 100,000s of plays of one of his tunes, making a living as a guitarist becomes nearly untenable. This is not a one time occurrence. Read Zoe Keating's article about how YouTube is treating her as they roll out their new music service. This same scenario is playing out in journalism, photography, etc. The creative classes are under siege. The attention economy provides a direct way for creative people to earn compensation for their creative outpouring. Facebook simply doesn't have such a model and it would directly undermine their existing revenue model.
5) Synereo provides users with a new level of control over what shows up in their feed. At this level of detail we can say that Synereo identifies two basic types of entities, ports and filters. A port can either be a source of information (like one of your friends from whom you receive posts, or an rss feed to which you are subscribed, or a mailing list to which you are subscribed, or a device on the Internet of things, or ...) or a sink for information (like one of your friends, or an rss feed to which you publish, or ... ). A filter is something applied to the stream of information flowing into or out of a port to further refine what goes into or comes out of the stream. Notice that when you combine a filter with a port you get a new port. This kind of 'algebra' of information flow components gives users a new toolkit for controlling what they see in their feed. It also has fairly natural UI metaphors that have a long history of success as a means of conveying the presentation of streams of events. This leads is to the last point.
6) Synereo provides new UI experiences that allow for users to see more about the dynamics of information flow. As a simple example, Facebook organizes the posts of all your friends into a single interleaved stream. If you were to uninterleave this into several streams that were synced by timestamp you would see how your friends' posts were related to each other in time. Picture in your mind's eye 5 timelines running left to right. One timeline for one of 5 friends. Each timeline provides an iconic representation of that friend's posts. When posts stack up in a near vertical line it means that your friends are posting at the same time. This gives you a way to see into the temporal dynamics of the communications of your group of friends. The reason i chose 5 is because there are 5 lines in a single musical staff. Just as the vertical stacking of notes on a staff represents play these notes at the same time, i.e. play a chord, chords in the 'score' representation of timelines allow for people to see how peoples actions are related in time. Any 6yr old can learn to read the temporal dynamics off of a single staff. A good conductor can read and hear in her mind 7 staves. So, the surface of inborn information processing capacity of the human mind for processing temporal dynamics is not even being scratched, let alone the depths plumbed. Facebook does not actually have a vested interest in users being able to utilize their capacity. They have a vested interest in directing attention in a way that maximizes return for their investors.