I'm not going to read that article. Replication is the ability to create a copy of itself as you'll see for backup/disaster-recovery or for distributed systems, such as a CDN.
Synchronous vs Asynchronous is how that backup is performed. Synchronous keeps all databases in sync. Asynchronous queues updates, which means if the primary server goes down before data is transferred, you might have data loss.
There are a number of replication features, such as load balancing or connection pooling. Postgres may not have them all, but it has a decent amount (there are 3rd party tools for what can't be satisfied by the native application).
There's a chance whatever you read was comparing older versions of both MySQL and PostgreSQL. However, you can always see more information about Postgres features in its wiki.