With apologies to Jackie DeShannon I would say: topic maps!
The music is a bit over the top but e-Discovery: Did You Know? makes the case for topic maps now!
My favorite line: “At our current rate of data expansion by just 2011. There will be 2 zettabytes of ESI [Electronically Stored Information] (2 thousand) exabytes), which is as many bytes of information as there are … STARS IN THE UNIVERSE”
My takeaway — the amount of mappable territory continues to expand. We can each find our own way or, we can join forces to create and share maps to what we have discovered and places we have been.
As Steve Newcomb foresaw years ago, there is a real economic opportunity in building maps into information territories. That is searchers can monetize their explorations of information resources as topic maps.
You can buy reports from Gartner but with a topic map of an information area, you can merge it with your data and reach your own conclusions.
A killer topic map application would pair itself with data exploration tools for easy creation of topic maps that can be refined as part a topic map creation process. (The tedium of matching up obscure musicians might appeal to ministry of culture types but insights into stock/bond trading, cf. The Big Short, legal discovery, medical research, are more likely to attract important users (the paying kind).)