..a class of software that is so rich in potentially useful features that even after years of use there is still more to be discovered.. And these aren’t useless features that bloat the product — rather the software is so mature and has been worked on by so many for so long that there is so much in it to explore.
There was on the thread, though, one nomination to the title of deep software that I simply can’t skip, because I happen to agree that the nominee is one of the best pieces of software there has been (and its author build it when he was, get this, eighteen; see Rolling Stones article on him) and because the nomination itself is just damn good writing.
…over the past few months I’ve become convinced that there were only two really revolutionary pieces of non-game software released in the 1990s that completely dictated what followed in their fields. One was NCSA Mosaic, and it doesn’t really fit into your criteria. The other one almost certainly does, though you don’t realise it until you really start exploring. Also, it’s not “productivity” software in the same sense as the others, but I think it’s inspired just as much creation.
Okay, enough with the hyperbole. Have one guess, and then click here.