T'Pol makes reference to a protocol which states that it is wise "to wait until a society develops warp drive before initiating first contact." She goes on to say that it would be wise for Starfleet to adopt these "Vulcan protocols." Starfleet later adopts them as part of the essential Prime Directive, serving as a benchmark for measuring development of a civilization and admission to the Federation.
This episode was in production on the Tuesday when the terrorist attacks of 11 September 2001 occurred in New York City, as well as at The Pentagon in Virginia and production was shut down for the day. In 2013, Mike Sussman stated that he still could not watch this episode as he could see in the footage the enthusiasm and light go from all the actors' eyes because of the events of 9/11.
Mike Sussman (writer) saw the incorporation of the Malurians here as an amusing in-joke, they having originally been mentioned in The Changeling (1967), as a species wiped out by Nomad.
The set for the antiques shop in this episode included items, seen on-screen, which were actually a variety of old props from the Star Trek storeroom.
This episode contains the first reference to Tellarites in Enterprise.