I forgot to post about the Facebook Iowa data center, and just sent this up a month late. :-)
The next interesting question is where Facebook will build next. I have some theories and I'll send some e-mails to some buddies and we'll chat about it next week. Then we'll see if I was right or wrong in about 6 - 9 months.
Speculating about Facebook's data centers in the media just makes things worse for everyone, except the media companies that are only interested in traffic. I don't think anyone has found that an early media disclosure of their data center plans has helped them.