Okay, WWBD. What would Buffy do? Huh?
When Supernatural started, comparison to the successful Joss Whedon shows Buffy the Vampire Slayer and Angel were inevitable. Like them, Supernatural featured ordinary people fighting the supernatural, as well as also airing on The WB where Buffy had started and Angel had aired until it finished in 2003. An early review of the "Pilot" described Supernatural as "X-Files meets the OC, meets Buffy type show from the WB."
Supernatural certainly attracted many viewers who had also been fans of the Whedon show. This can particularly be seen in Supernatural/Buffy crossover fanworks, like the pairing of Dean with the rogue slayer Faith.
Buffy fandom invented the term Jossed - to be jossed is to have fan theories or events in Fanfic be invalidated by new canon in the show. By contrast Kripked was a term coined in Supernatural fandom to refer to having fan theories supported by canon. See also Fan Fic Cliches.
The most significant crossover between the series is Ben Edlund. Ben started working with Joss on Firefly before moving to Angel for the last couple of seasons. He wrote and directed the Hugo nominated episode "Smile Time" aka the one where Angel gets turned into a puppet. Keith R.A. DeCandido has written tie-in novels fro both Supernatural and Buffy.
Many actors from Buffy and Angel have appeared on Supernatural -- the first were Amy Acker who appeared in 1.03 Dead in the Water and Julie Benz was in 1.12 Faith. Following Amber Benson's appearance as Lenore in 2007, EP Bob Singer said "I thought Buffy had a great cast, and we used Amber Benson. I’d like to get Spike [James Marsters] on our show. I never thought I would particularly like Buffy, but my wife got me hooked on it, and I was hooked on him. Plus, that series was so well written. It was so smart." (Source)
Other Whedon alumni who have appeared on Supernatural include:
|Actor/Actress||Role on Supernatural||Role in Whedonverse||Whedonverse Show|
|Jeffrey Dean Morgan||John Winchester||Sam Ryan||Angel|
|Robert Peters||Deputy Hein||Arney||Angel|
|Amy Acker||Andrea Barr||Winifred Burkle / Illyria||Angel|
|Kristin Richardson||Jenny||Tracy Bellows||Angel|
|Julie Benz||Layla Rourke||Darla||Buffy the Vampire Slayer and Angel|
|Megalyn Echikunwoke||Cassie Robinson||Vaughne||Buffy the Vampire Slayer|
|Ridge Canipe||Young Dean Winchester||Tommy||Angel|
|Chad Lindberg||Ash||David Kirby||Buffy the Vampire Slayer|
|Amber Benson||Lenore||Tara Maclay||Buffy the Vampire Slayer|
|Annie Wersching||Susan Thompson||Margaret||Angel|
|David Monahan||Father Thomas Gregory||Garrett||Angel|
|Jeff Kober||Randall||Zachary Kralik and Rack||Buffy the Vampire Slayer|
|Aldis Hodge||Jake Talley||Masked Teen||Buffy the Vampire Slayer|
|Mercedes McNab||Lucy||Harmony Kendall||Buffy the Vampire Slayer and Angel|
|Aimee Garcia||Nancy Fitzgerald||Cynthia York||Angel|
|Brittany Ishibashi||Maggie Zeddmore||Vivian||Angel|
|Todd Stashwick||Dracula||Vocah (Angel) and M'Fashnik Demon (Buffy)||Angel and Buffy the Vampire Slayer|
|Jack Conley||Sheriff Al Britton||Gib Cain (Buffy) and Sahjhan (Angel)||Buffy the Vampire Slayer and Angel|
|David Mattey||Luther Garland||Behemoth Lorne||Angel|
|Bradley Stryker||Ted and Tony||Talky Meat||Angel|
|John Rubenstein||Charlie the Magician||Linwood Murrow||Angel|
|Rob Benedict||Chuck Shurley||Jape||Buffy the Vampire Slayer|
|Jack Plotnick||Ian Johnston||Deputy Mayor Allan Finch||Buffy the Vampire Slayer|
|Charisma Carpenter||Maggie Stark||Cordelia Chase||Buffy the Vampire Slayer and Angel|
|James Marsters||Don Stark||Spike||Buffy the Vampire Slayerand Angel|
|Henri Lubatti||Bobby's Reaper||Dealer Vampire||Angel|
|Harry Groener||Professor Morrison||Mayor Richard Wilkins||Buffy the Vampire Slayer|
|Bryan Cuprill||George||Roy||Buffy the Vampire Slayer|
|Felicia Day||Charlene Bradbury||Vi||Buffy the Vampire Slayer|
|Tamara Braun||Cindy Cassity||Tara||Buffy the Vampire Slayer|
|Brigid Brannagh||Rita Johnson||Virginia Bryce||Angel|
|Keith Szarabajka||Donatello Redfield||Daniel Holtz||Angel|