Okay, maybe "finally" is going too far. They're not there until the Dark Knight and the Man of Steel are allowed to make appearances in live action television as easily as other random DC characters, but this week's episode of Flash finally showed DC is starting to realize how popular shared continuity is.
The Flash, of course, spun off from the successful series Arrow. A second spinoff with various DC characters pulled from both other shows called "Legends of Tomorrow" is also running. That's not what I'm talking about. I'm talking about a single episode of Flash, where Barry Allen and Vibe jump across to a different Earth (Earth-Two). During the travel, they see visions of other realities. What was the first vision we saw?
Yes, that's Melissa Benoist from Supergirl on CBS (despite Flash airing on CW). Turns out they're even doing a crossover episode this season.
Jonah Hex also shows up in the montage, as does Connor Hawke, and John Wesley Shipp's Flash from the 1990s.
Earth-Two's Barry Allen has a speed dial with names that include Bruce, Hal, and Diana. (Hmmm.)
Couple that with NBC's John Constantine showing up on an episode of Arrow this season after his own show was cancelled, and could it be that Warner Brothers is finally seeing the wisdom of linking all their DC series, if not in a "Shared Universe," at least in a "Shared Multiverse?"