User blog comment:Forrestib/Crossover/@comment-25405817-20141220023541/@comment-73.42.187.52-20141221221131

I never said video games comics and kid series as a whole have no proper continuity, but specifically most of your examples do not, and the majority that go mainstream and become multi-platform franchises do not, specifically because the problem with multi-gen/multi-platform is that there is usually a need to do the origin story multiple times and reboot the series, or as I said was the case with those 2 nicktoons, you keep the character in a perpetual state of no real, lasting, growth for as long as possible.

"Excluding anything that doesn't have lasting influence to the plot of both worlds AND anything between franchises with a shared production company"

I never excluded the latter, I consider Buffy/Angel successful crossovers, SAO/Accel World, I also consider marvel/DC(both in-house and with each other in general) crossovers successful for that medium(as they have multiple universes to explain them, and because they have so many universes they can just drop the universe the crossover existed in and have no lasting impact), as well as Dr. Who and most of it's own crossovers/spin-offs, generally, I consider any crossover that easily passes as a normal episode in either series successful, so long as the crossover doesn't break the flow of either series.

as for my remarks about franchises, they have to deal with the creation of a crossover, not the requirements of being a crossover.

a crossover is created because both franchise have something the other wants/needs, often this is the fandom, sometimes it is the technology and the problems/solutions they offer, sometimes it is the villains/world/or heroes, but most often, they offer history and a full world apart from the one the Heroes from one series are in, they make a platform where minimalism is possible while maintaining surprises for the mc's while the reader can see most traps coming from a mile away, as well as determining whether or not the trap going off in the face of the character even affects them.