I've been reading a great armchair physics (my favorite kind of physics) book recently and came across a great line, by the author, Lawrence Krauss. He was discussing the rapid increase in computing speed and memory (which was especially fun because it was published in 1995), but he put the prime limiting factor of information processing, rightly, at the human end of the chain...
I find already that the rate-determining step in the information superhighway is the end user. We can assimilate only so much information...I am not limited by my computer's capabilities but by my own capabilities.
I suppose it's both capabilities to some extent, but when it comes to driving understanding and providing context, the real (and cost effective) progress is in the thoughtful and meaningful arrangement of information in a manner that fits with the ways and speeds that our minds can process it.
Even (especially?) for mission-critical apps, the attention budget is tight. There are waves of communication that an info designer has access to as a user navigates and that initial visual tier has the potential to be anywhere between superficial and wasted, to carefully balanced and insightful, to destroyed by a kitchen sink info-dump.
P.S. The book is The Physics of Star Trek, which I bought for a penny -an excellent per-pound cost.