I just got a chance to go through the just-leaked IAEA report on Iran's nuclear program now, but one thing I'd already noticed is that despite the write-ups of the findings being characteristically damning, no one really paid any attention. Either everyone has been too busy to take a close look, which is possible, since I certainly was. Or else there's a "violation fatigue" that has set in, whereby the consensus understanding is shifting toward accepting that Iran simply won't stop its enrichment efforts, whether in LEU or 20 percent enriched uranium.
If that's true, it will probably take something even more arresting than the revelation in September 2009 of the previously undisclosed installation at Fordow to shock everyone into recalibrating their outrage meters. Trouble with that is that there really aren't that many arresting developments left beyond a smoking gun on weapons payload research and development, or weapons-grade enrichment capability. Even if you don't take the Israeli threats to bomb Iran seriously (and I don't), that's still a major shake-up.
There's another possibility, whereby Tehran is plowing ahead with its enrichment in order to create the most advantageous facts on the ground before striking a deal (sort of like the Israeli settlement policy on the West Bank), and Washington is maintaining a low-key response because the right backchannels signals have been sent.