First episode to feature Starfleet officers wearing the new gray-top uniforms, which first appeared in TNG film Star Trek: First Contact (1996). While this uniform change covers the entire reach of Starfleet, the crew of sister show Star Trek: Voyager (1995) continues to wear the original DS9 uniforms, as they are lost in the Delta quadrant when the change is made.
The scene with Sisko carving shapes into the melon was intended as a homage to the famous mashed-potato scene in the Steven Spielberg film Close Encounters of the Third Kind (1977).
Another part of the B'hala excavation site was visited by Sisko in the sixth season episode The Reckoning (1998).
Sisko had previously suffered "an excess of neuropeptides" at the same time as an orb shadow (in this case, a vision of Kai Opaka) in the fourth season episode Accession (1996).
In this episode, Kira makes it explicitly clear for the first time that she is happy for Bajor to join the Federation, acknowledging the contrast to her opinion of five years ago, as seen in such early episodes as Emissary (1993), Past Prologue (1993), and In the Hands of the Prophets (1993), and accrediting the change in her feelings to her time on the station and the influence of Captain Sisko, whom, of course, Kira sees as the Emissary of the Prophets.