I put in the link address above. When I tried to create a link with http:// , with or without <a> tags, a box in red appears which reads: "Links to arXiv:0904.2715 are not allowed."

Thanks, quid. It was through google, but apparently I hadn't cleared the cache before (thought I had). The problem is fixed now (sorry for noise, but I'll leave this question up just in case it helps anyone else).

Agreed, ability to edit comments is nice. If you're asking did the notification to me work, then "yes". And I'll say I had a positive exchange with SE support wrt to getting my account properly up and running, so that's a good sign as well. Oh, @JonBeardsley.

Um, why don't we really deserve it? And indeed, why is it so awesome? In other words, what makes you say that? I'm genuinely curious...