I don't know why it is not functioning these past few days but here's an alternative.
Theymos responded to a similar inquiry some days ago with a general reply:
The index is being rebuilt. It's taking a little longer than I remembered from last year: it might actually be tomorrow or the next day before it's done...
The process is most certainly still being worked on as it's still down, so, for now, the forum Google search option is the alternative (it's actually my most preferred of the two options). Probable check back at the end of today.