[stephane-klein]

I read here https://www.fediscovery.org/ :

  > How is this related to relays?  
  >  
  > Relays can be used to get a more complete view of what is going   on in the larger  
  > Fediverse. As such there are some similarities to this proposal.  
  >  
  > From an instance operator’s point of view the biggest difference is that using a relay
  > comes with a higher cost. The instance needs to ingest and index everything the relay
  > sends which takes up processing power and storage. A discovery provider will do that
  > work for one or more instances.
  >
  > Implementation-wise we expect to see some similarities with how relays work, at least
  > for real-time data. But discovery providers should be able to index historic data as
  > well. So ingesting real-time data from instances is only part of the story.
  > Querying instances for historic data is not currently something that relays do.