(I'm teaching this summer. I'm also traveling this week. I typed this up for the class as a way to think about the depth of engagement of the communications they design.)
While brevity is great, do not conflate it with inadequacy. As designers, you need to communicate on levels that are succinct at the surface, but give an opportunity to "dive in" a bit more if the reader has the time or inclination. Sometimes, I call this the 2-second, 20-second, 2-minute + 20-minute read (and 2-hour read, if appropriate).
Imagine yourself at the airport waiting for your plane. You're at the newsstand. You look over at the magazines and all have a 2-second read on the cover. This entices you and tells you immediately, through visuals and text, which one might suit your fancy. You pick one one — Shape magazine, because you're on a fitness bender.
Thumbing through the magazine quickly, even for 20-seconds, you get a very good idea of what the entire magazine is about.
You check your watch... Dang! You still have quite a while before your plane begins to board. You give the magazine another flip-through and this time look a bit deeper into some sections — you get a bit more out of that pass (and in some areas more than others in particular) with a 2-minute pass through the magazine.
You hear an announcement that your plane is delayed and you figure: Heck, it's a good magazine... and buy it. You sit at the gate area and start to read deeply into a single article — the 20-minute read.
Your plane boards and you settle in for a long coast-to-coast flight only to discover that your iPad battery is a 2% — Dang! ... good thing you bought that magazine. You settle in to read the magazine from cover-to-cover for the 2-hour read.
Designers are challenged everyday to tailor their communications to the ways in which the audience will best absorb them, but even then, it's hard to tell exactly how it might go. In this case, your audience is a fitness-minded person with extra spending money (for magazines). But if they have little time or a lot of time is hard to tell (and might even vary from person to person), so giving them something at every level of engagement is a wise move.
(How can you use this the next time you deliver something to an audience?)