This is a really good thing. One, it means that eSATA will be coming sooner rather than later to Macs. Apple even sell a RAID unit, the Promise SmartStor DS4600, that on the Apple site has no mention whatsoever of eSATA, however it’s there on the box, and mentioned on the Promise web site. Target Disk Mode is one of those things that you don’t use often, but when you do need to use it, I can’t imagine doing it any other way.
Say you get a new Mac. Boot the old one in target disk mode and the Migration Assistant will set up your new machine from the old one. Have a Mac that won’t boot? Boot it in target disk mode and plug it into another one to run disk utilities. Need to transfer large amounts of data from one machine to another and don’t have Gigabit Ethernet, or haven’t set up a LAN and file sharing? Target disk mode to the rescue again.
At present, this only happens over FireWire, and not over USB. Now that Apple have the patent to do it over eSATA, I would expect to see the introduction of eSATA ports on high end machines first (Mac Pro) and then having them trickle down to the iMac and then the Mac mini. Maybe we’ll be graced with them on laptops, but I’m not sure on this one…
via Infinite Loop on ars.