What is Peacock, you ask? Great question. It's NBCUniversal's new streaming service that aims to deliver original TV series while also offering up a ton of titles in parent company Comcast's catalog. Today, certain Comcast subscribers will have preview access for the service's ad-supported option, Peacock Premium; all Comcast customers should have access to Peacock by the end of the month before the national rollout on July 15th. But just what separates Peacock from the likes of mainstays like Netflix, Hulu, and Amazon Prime, upstarts like AppleTV+, Disney+, and the upcoming HBO Max, and non-…