FETHR (Featherweight Entangled Timelines over HTTP Requests) is, AFAICT, an application-level multicast protocol on top of HTTP using JSON packets protected by hash checksums.

Interesting things seen in the presentation held at IPTPS'09:

  • Solving the unicast problem is not so important, since 90% of Twitter users have less than 100 subscribers. 99% have less then 600. Only the top ten has about a million subscribers each.
<lynX> But these are just 2009 numbers of Twitter, which isn't even the most popular social network on the Internet.
  • FETHR goes on to solve the unicast problem anyway by proposing a solution called Gossip, which is actually a multicast strategy among subscribers of a feed.
<lynX> Sounds much better.  ;-)
  • Messages are signed.
  • Timeline integrity is protected by hash chains (instead of just using a counter like PSYC intends to, FETHR sends the hash of the previous message along with every new message, so you can recover it by means of a hash instead of a packet id)
<lynX> I presume both methods work.
  • Implementation of FETHR is already available. Seems to be enough for doing decentralized Twittering.
<lynX> Is this server-based? The majority of people don't own a server. That's why we are looking into F2F topologies.