fyi, i finally just finished season 1 due to netflix adding it, so i know i'm late on this... a few pages back we were talking about amazo and whether or not the mention was a sign of things to come, or just a nod to dc comics... from what i understand, it was just the one mention, which means to me, that it was just a nod to dc continuity. i think people missed a lot of those in season one because they were done so subtly. for instance, in the episode after walter comes back (Season 1) when they show the flashback were merlyn says he wants to blow up the glades, moira asks robert queen specifically, "i thought this was just another Ted Kord fundraiser." for those of you not in the know, Ted Kord is the original Blue Beetle and a fan favorite.
i don't remember what else, but i know there's been a bunch of one-off comments about dc continuity, including mentions of places like coast city. as someone else said, this show moves too quickly for them to drag out an introduction to a character. flash seems to be the only exception, though we all know he's coming.