there's no change to the revocation of bad certificates, which is still done by the CAs.

certificates continue to be issued and revoked as they always have been

Finally, everyone who interacts with logs should check with each other that they have all seen the same log—that is, that the log is not presenting different views to different people.

The core idea behind Certificate Transparency is the public, verifiable, append-only log.

Whenever a client connects to a server, it sends a few items to the server, which the server may verify or merely cache; in return the server sends a few items back from its cache. This establishes what is effectively a peer-to-peer network between the clients.