Created an account to reply here. I had my interview on April 24th 2014, for a first time H1B stamp, and was given a 221(g) yellow form, presumably due to the nature of my graduate research. I anticipated that something like this would happen, so I prepared for the worst case scenario. It's been a little over 3 weeks now, with no updates on the CEAC website as yet. I suppose there's not much to do but wait. I'll post any updates as and when they happen.