Update PUBSUB_AT_SCALE.md

OPEN_PROBLEMS/PUBSUB_AT_SCALE.md

@@ -5,7 +5,7 @@
 
 Publish/Subscribe (pub/sub) messaging systems have been proposed and traditionally used to disintermediate senders and receivers of messages. That is, in pub/sub systems, publishers of content do not send the published messages directly to one or a group of receivers, but instead *publishers are sending messages to a topic.* The pub/sub system then needs to match subscribers' interests to published messages, or more commonly known, events. This model of communication enhances asynchronous communication and reduces tremendously network traffic and bandwidth-requirements.
 
-*Within the IPFS and libp2p ecosystetms, pub/sub is being used to push naming record updates to the decentralised Naming System of IPFS, acronymed IPNS* (https://docs.ipfs.io/guides/concepts/ipns/). As the IPFS system is evolving and growing, communicating new entries to the IPNS is becoming an issue *due to the increased network and node load requirements*. The expected growth of the system to *multiple millions of nodes is going to create significant performance issues*, which might render the system unusable. Despite the significant amount of related literatture on the topic of pub/sub, very few systems have been tested to that level of scalability, while those that have been are mostly cloud-based, managed and structured infrastructures. Instead, in the case of IPNS (and IPFS more in general), *the network is totally decentralised and therefore unamanged*. This poses new challenges to the pub/sub protocol, which we want to explore through this RFP.
+*Within the IPFS and libp2p ecosystetms, pub/sub is being used to push naming record updates to the decentralised Naming System of IPFS, acronymed IPNS* (https://docs.ipfs.io/guides/concepts/ipns/). As the IPFS system is evolving and growing, communicating new entries to the IPNS is becoming an issue *due to the increased network and node load requirements*. The expected growth of the system to *multiple millions of nodes is going to create significant performance issues*, which might render the system unusable. Despite the significant amount of related literatture on the topic of pub/sub, very few systems have been tested to that level of scalability, while those that have been are mostly cloud-based, managed and structured infrastructures. Instead, in the case of IPNS (and IPFS more in general), *the network is totally decentralised and therefore unmanaged*. This poses new challenges to the pub/sub protocol, which we want to explore through this RFP.
 
 ## Long Description