You may have recently come across an "infographic" of the best-selling sci-fi books of all time—it was reblogged by New Yorker and Flavorpill. Unfortunately, this long list of books is just that, a long list of books. It doesn't follow any particular order, doesn't use any identifiable system of visual elements that corresponds to a pattern in data, doesn't even list the source of data used (the sources it lists make no mention of the data). So basically, this piece of crap doesn't qualify as an infographic (that it's just a big image file lends it no credence).
An infographic, at its bare minimum, must (1) use data that was measured against a single variable at a time, and (2) have a simplified visual system to represent this data. If you're showing total sales of a book inside a drawing of book for one book, but not for another; and if the scale or color (or something other) of that book drawing does not actually say anything about the relationship of that number to the whole, then that is not a system. That's just some random bullshit. Also, you can't measure total sales for one book in Japan, and worldwide for another. As for a good infographic, the information it represents also reveals, at a quick glance, the overall pattern in the data (for example, the subway map is a simplification of the relationship between geographical data and different train lines; it shows, clearly, which trains run along the east side, which train lines are the longest, and so on). And if an infographic can't do all that, well then it must at least be pleasing to look at! So here's my sincere (in this age of unbearable irony, we've been told) feedback to the person who made this "infographic."