Board Thread:General Discussion/@comment-24744495-20140625045639/@comment-252417-20140626083925

Kiki38117 wrote: I'm pretty sure everything until Scooby Doo Mystery Inc. is in the same universe, canonical mistakes make you think otherwise but in one episode of What's New, Scooby Doo we found out that the gang is the same as in APNSD, and in  Aloha, Scooby Doo (which is same  univers as Whats New, Scooby-Doo) Shaggy mentions Scrappy in Extra scene You pretty much summed it up. Retcons can be a pain, but it's pretty much all the same thing.

Get a Clue is also considered a seperate entity here, not only because of the drastically different animation and the way they've been characterized, but because one episode distinctly had Scooby and Shaggy have different companions before they met. This is a big continuity error as they've known each other practically since birth. Of course, it's not a continuity error if it's supposed to be set in an alternate universe.