User blog comment:Nobody700/Arrow Reviews: Episode 43: Carry on, wayward Mother/@comment-27700324-20161024032844

In Marvel comics, their adventures are written in the form of comics inside the stories. Sometimes the characters would meet the writers and editors.

In DC, they kind of just mention some comic book characters that aren't created by DC, but they are too vague to get sued. (e.g Supergirl reading a Spider-man book given by Jimmy.)