In Potential, Dawn reminds the Scoobies that she saw her mother in Conversations with Dead People, and reveals that she’s privately still concerned about what her mother said to her:
Dawn: “Guys, when Mom appeared to me she said…”
Willow: “Dawnie…”
Dawn: “No, please. She said something about Buffy and I’m thinking… I’m …

In Potential, Andrew asks if they’re going to get the microwave fixed, a reference to Conversations with Dead People when Dawn smashed the microwave after it went all evil. In First Date, we see Andrew setting up the new microwave and reading the instruction manual: “‘Getting the most out of …

As the Scoobies and potentials start their battle with the Turok-Han in Showtime, we’re unaware of Buffy, Xander and Willow’s plan. We later see a flashback to their telepathic conversation discussing a way to improve moral. A similar use of flashback was used in Chosen, when Buffy’s final speech to …

In Bring on the Night, Buffy stakes the Turok-Han but it doesn’t dust, though we learn in Empty Places and Chosen that the Turok-Han can be staked. In Faith, Hope and Trick, Buffy staked Kakistos, which was also ineffective. It took Faith with a massive beam to finally dust Kakistos.

The metal sign on Principal Wood’s desk says ‘Jonathon M. Wood. Principal’, so Robin may be a pet name. The actor who played Holden in Conversations with Dead People is called Jonathon M. Woodward.

The Watcher’s Council Headquarters in London, including the head, Quentin Travers, and many other staff members, is blown up in Never Leave Me.

Dawn doesn’t own a dog, yet despite this she still has an ‘Everything I Need To Know, I Learned From My Dog’ poster on the back of her door (seen in Never Leave Me).

Tom Lenk, who played Andrew, appeared in every episode in season seven after he was captured by Willow in Never Leave Me.

In Conversations with Dead People, Dawn talks to her friend Kit on the phone. The two met in Lessons on their first day at Sunnydale High.

In Seeing Red, Buffy finds the nerd’s new ‘lair’. There, she picks up some papers and you can see that there’s nothing on the back of them. In the next shot, there’s writing on the back of the papers.

Buffy puts pancakes on a plate for Dawn, then the two discuss Dawn patrolling with Buffy. Then at 16:15 we see that the pancakes have disappeared, without Dawn eating them.

In As You Were, Sam says “We’d better regroup”, but her lips aren’t actually moving

In What’s My Line, Part Two, Patrice (the assassin disguised as a policewoman) pulls a gun from her holster, which Buffy knocks out of her hand. Then she pulls another gun from the same holster to fire the shot that hits Oz. Two guns in one holster?

In Tabula Rasa, there is a replica of the two faced statue Janus behind Giles when he finds his airline ticket in his pocket. The statue was seen first used by Ethan Rayne in Halloween.

In Killed by Death, when Buffy is sick in hospital, the shot focusses on a clock on Buffy’s bedside, which clicks over to 2:27. In the next shot of Buffy, the clock reads 2.15.