There is some prototype work done in master already (if you build go-ipfs from source).

   $ ipfs pubsub --help
   
   USAGE
     ipfs pubsub - An experimental publish-subscribe system on ipfs.
   
   SYNOPSIS
     ipfs pubsub
   
   DESCRIPTION
   
     ipfs pubsub allows you to publish messages to a given topic, and also to
     subscribe to new messages on a given topic.
     
     This is an experimental feature. It is not intended in its current state
     to be used in a production environment.
     
     To use, the daemon must be run with '--enable-pubsub-experiment'.
   
   SUBCOMMANDS
     ipfs pubsub ls                    - List subscribed topics by name.
     ipfs pubsub peers                 - List all peers we are currently pubsubbing with.
     ipfs pubsub pub <topic> <data>... - Publish a message to a given pubsub topic.
     ipfs pubsub sub <topic>           - Subscribe to messages on a given topic.
   
     Use 'ipfs pubsub <subcmd> --help' for more information about each command.