Maybe the network is getting really, really, really lucky.
How long have we been "lucky"? Depending on how many blocks you look at, you might come to different speeds and different volatility of the speed measured.
http://bitcoincharts.com says 23.762 Thash/s
http://bitcoinwatch.com/ says 16.99 Thash/s
http://bitcoin.sipa.be/ says 20 Thash/s
The last retarget sets the difficulty according to about 16Ghash/s.
I can't see anything in the charts that would get me excited (and this thread almost got me to spam my poor Facebook friends about bitcoin again. +10TH in one day after pirate announcing to pay back his dept just sounded too juicy.)
