Note that, distorted as they are, the human figures in all of these images obey a set of strict rules.  For example, they all keep the same proportion of a large puffy body and small head and limbs; they can only have an angle on the internal side of a limb, while the other side is a smooth curve; all of them are shown in an emphatically dynamic, non-linear and horizontally stretched context, etc.  By failing to comply to one of these rules, which are immediately obvious to the viewer (although not necessarily on a conscious level), a picture in the series would be damaged much more seriously than by the lack of photographic likeness. Thus, the author has created his own world with a recognizable look and feel, and this achievement provides a much better chance of pleasing modern audience than sticking with graphic realism.  You can convey a surprisingly wide range of moods and attitudes if you find an original style to express yourself, and although most of these attitudes are likely to contain a certain degree of irony (it's difficult not to be ironic when knowingly distorting something), they perfectly match the prevalent style of modern business communication, with its craving for originality and aversion from "plain boring" solutions. Let's repeat: Drawing is hard, it's definitely not a skill to be taught to everyone.  But, I dare say that drawing in the "my own world" style is accessible to almost any person with good aesthetic sense after some self-training and practical experience.  I don't know whether the author of Adobe Acrobat imagery has ever undergone a formal academic training in drawing techniques or human anatomy, of the sort that was obligatory for an artist apprentice a century ago, but I know other people who create amazing artwork without such training.  (On the other hand, a formal training would never hurt, and although modern art may have redefined the notion of professionalism, it hasn't of course abandoned it.) There are also some formal features worth noting.  Since in the real world, crisp edges and color boundaries are always alternated with blurs and gradients (which is the fact responsible for the peculiarity of photographic textures), in realistic images contours are rarely closed curves continuing each other.  Instead, lines in such drawings tend to start and end "in the air" - much as in the real world, the characteristic outlines of an object are floating in the ocean of blurs and unimportant details.  It does indeed take an above average drawing capability to sculpt a perfectly life-like form by a few pencil strokes, with no shadows or color to assist, and the results of this sort are particularly impressive. On the contrary, the ironic and distortive "my own world" imagery most often has an outline in proper sense of the word, represented by a structure of prominent, usually quite bold lines separating objects from each other and the background.  For example, the Acrobat images just discussed would obviously keep most of their impact if their color fills were removed, leaving only the black outline.  This explains the fact that objects in these images look rather flat (since the outline is busy delineating the exterior of objects, it cannot help in bulging them in the third dimension), and their lines form closed regions like those on cartoon cels (the last word being derived from "celluloid," it also incidentally reflects the cartoon drawing style with its "cells" of flat color with prominent contour). Seriality is also a very important feature.  A single image of the style in question would have a smaller impact, and the percentage of viewers just ignoring it as "weird" would be higher.  Hence another hint for aspiring artists: Once you think you've found some interesting look in one draft, try to develop it further, make as many sketches in this style as you can, and select a few of the best ones for your design job.