Season seven is the only season without a Halloween episode.
Hey! What was that spark?
Sabrina: Um, static electricity?
Throughout out the series, it's clear that many of the actors/actresses portraying teenagers are actually in their 20s+. This is done as to not interfere with the schooling of real teenagers and to give the general viewing audience who are teenagers (or young people) themselves someone they can look up to.
In the first three seasons of "Sabrina, the Teenage Witch", Sabrina appears in differing clothing, and quotes a quick one-liner based on the subject of her clothing.
There are 2 endings to the episode "Inna-Gadda-Sabrina", the first one involves Salem leaving for Philidelphia (which explains his appearance in "Boy Meets World") and the ending in other airings and syndication involve Salem getting the time ball out of his system by using the litterbox (off-screen).