Jeff Garzik received an Avalon miner on january 30th, 2013 and posted pictures at http://garzikrants.blogspot.com/2013/01/once-upon-time-in-china-package-shipped.html and http://garzikrants.blogspot.com/2013/01/avalon-modular-room-to-expand.html
The next day he posted a review at http://garzikrants.blogspot.com/2013/01/avalon-asic-miner-review.html
For many this was a milestone that you might call the beginning of the ASIC era. Of course the manufacturer had the first bitcoin ASIC chip operative long before this. Also, this did not mean that you could just order an ASIC miner and receive it within a reasonable timeframe. But it did mean that the first bitcoin ASIC machine had shipped. For better or worse, it had begun.