These are the tweets , that started the wild speculation. https://mobile.twitter.com/gregorythesmith/status/479333463825203201
Hope that works for the newbie.
Sorry for essentially repeating post.
I'd upgrade that from possibility to almost certainty. The furore over a tweet between Stephen Amell and another actor, Gregory Smith today was enough to send people speculating wildly about whether he was 'Daniel'.
Newbie coming out of lurkdom to say that I have only heard of Eric Oleson who tweeted on @Arrowwriters and is listed as a co-executive producer.
https://twitter.com/erikoleson/status/474661074256822272