The OpenPGP SKS keyservers are broken because they are append only. So script kiddies can do stuff like signing a particular key zillions of times or swamping the servers with zillions of bogus OpenPGP identities. Afterwards there is no way to fix things.
The system discussed in the article (Parakeet) is also append only. So it would be vulnerable to the same sort of attacks. The difference is that it can eventually expire old entries in a reasonable way to free up resources. So no help against signature attacks but possibly of help against the resource usage of bogus identities. The bogus identities would still exist though.
I think there might be merit to the overall idea of having a semi-trusted entity in charge of the system and then making it so that others can judge that what that entity is doing is reasonable. Still a problem if the entity goes rogue and you have to replace it. I suppose that is a problem in the Whatsapp case as well.
I think this is interesting since Apple is also turning key management over to the Users. Identity Key management seems like the next step in the App Store dance.
Warning this is all my opinion and one should use their own judgement.
Apple's whole identity system is basically kerberos+ldap. This is how Apple deals with identity and authentication. Apple has made recent announcements at handing this management to the user. This is how Apple will open up the App Store. There will be a status quo set-up and an open set-up. The status quo will be for those who could give a flying flip about all the freedom people claim they are missing out on. The open set-up will let the identity owner share their keys with anyone they one want. Apple can use all sorts of alerts and lock down all of data held by Apple and the user can create and share keys with whoever they want without providing unintended data access held by Apple. Facebook users will create keys to use with their iOS device and and that will be the point that FB can start to collect data. The only thing this is based on is my Sysadmining Macs since about 1989.
The system discussed in the article (Parakeet) is also append only. So it would be vulnerable to the same sort of attacks. The difference is that it can eventually expire old entries in a reasonable way to free up resources. So no help against signature attacks but possibly of help against the resource usage of bogus identities. The bogus identities would still exist though.
I think there might be merit to the overall idea of having a semi-trusted entity in charge of the system and then making it so that others can judge that what that entity is doing is reasonable. Still a problem if the entity goes rogue and you have to replace it. I suppose that is a problem in the Whatsapp case as well.