WebObjects is a web application framework. It's OLD old. It's about ten years older than Ruby on Rails, putting it on par with PHP and Ruby itself. NeXT made it and Apple decided to make it free. It was Objective-C and is now Java.
I used WO in the late nineties and it was way ahead of its time. Enterprise Objects (which morphed into Core Data) was an amazing tool for working with databases. Today it's pretty obsolete and it's not easy to find people.
It's not any older than Interface Builder and other stuff in the Mac OS dev toolkit, as all of that came from NeXT. I would guess though that it has not been maintained or updated.
