This guy "loves world maps" but chose Mercator for the wall of his room? I guess there's no accounting for taste. There are hundreds of projections to choose from, why choose the one optimized for navigation by compass?
The Mercator projection was indeed originally designed for compass navigation, but the reason it's still used for web mapping is slightly different. The Mercator projection is conformal. What this means is that angles (and hence in some sense shapes) are preserved locally. When we zoom in on a small section of the Mercator projection, we get a reasonably accurate representation of the actual shape of features. This is generally not true for most more fashionable projections, which will stretch and skew things, so they don't always look great when zoomed.
In general with map projections, you have to make a compromise between global properties and local properties. Choosing Mercator means going full-on for local quality, at the expense of the global map being quite distorted. This makes it great for zoomable web maps, because most of the time the global map is just used to find the area you're actually looking for.
Now, you could argue that for a living-room wall, you want something that looks good globally. If it was my wall, I'd agree with you. However, this guy seems to be really interested in local detail. He worries about his four-point fonts becoming blurry, and about having as many small villages marked on the map as possible. If he's interested in that kind of detail, then I think he probably cares far more about local properties than the kind of global properties that would bother me or you.
Just speculating here, but it's also a big rectangle that is easy on the eyes. Non-rectangular online maps would fit awkwardly in websites. As for Gall-Peters, that map is just irredeemably ugly to me, and I'm ignorant of other rectangular projections that could compete with Mercator.
As for other rectangular projections, the most common is the equirectangular (or plate carrée), which simply maps (longitude, latitude) to (x, y). This is a pretty common representation for gridded global data.
However, online maps alter the projection as you zoom so this is not much of an issue.
I'm also not aware of any of the main online maps changing projection as you zoom. It seems like that would be more pain than it's worth.
The property they both preserve is points north, south, east, or west of them on a globe are also north, south, east, or west of them in the projection. (Plenty of rectangular projections don't have this property ex: http://geographer-at-large.blogspot.com/2011/08/fun-with-map...)
The issue is interior angels of a triangle on a sphere don't add up to 180 degrees so you literally can't preserve all angles on a projection.
PS: If you actually walk exactly 1 mile north, 1 mile west, 1 mile south, then 1 mile east you don't necessarily end up on exactly the same place on a globe. (It does work if you start half a mile below the equator.)
Edit: Not that the earth is even a sphere...
I really like the "classic Guyou" projection: http://www.progonos.com/furuti/MapProj/Normal/ProjConf/Img/Z.... It mangles the ocean pretty badly, but the sizes and shapes of the landmasses are surprisingly realistic, and it's rectangular to boot.
But referring back to the OP, notice the grid of books and curios along the entire neighboring wall, and the grid-like pattern of the wood flooring underneath. The Mercator projection seems of a piece with this grid theme in the room.
Your curvy Guyou projection would look great in this Lautner house: http://cdn.cstatic.net/images/gridfs/53e53330f92ea16cd900340...
I don't think so at all. Australia is fairly balanced east/west in real life, but on that projection it looks like it's got an eastern tumour. Africa looks like it's got a western tumour. Spain looks like it's the size of the Arabian Peninsula. The British Isles (300k sq km) are the same size as India (3M sq km). It looks horribly distorted compared to a map on a globe.
Based on this image: http://www.dominik-schwarz.net/potpourri/worldmap/images/DSC... the entire continent of Africa looks only slightly larger than Greenland (when in fact it's about 14 times larger), and substantially smaller than Russia (when it is actually ~1.7 times larger).
Greenland has a population of ~60,000. Africa has a population of ~1.1billion.
I think Africa would have more small villages than Greenland (and Northern Russia) combined, yet is afforded less space.
I am surprised people who read the article are even asking this considering how much he struggled even to get the source image (and how he ultimately wound up manually stitching together print screens).
I can understand why someone wouldn't want to set up their own tile rendering system (and hence not use something like OSM with whatever projection they want), but it likely would have been less work than screenshots.
"What the hell is that?"
"It's where you've been living this whole time"
Still better than no map on the wall. The style looks lovely at this scale! I would have made my own map from NE and OSM data but not everyone knows how much great data is available for free and how easy making maps with it is. We who know should do a better job of sharing.
On some level this is an unsolvable problem, but I was disappointed to see him spend more time on the pins he used than on the tradeoffs involved in the projection.
https://developers.google.com/maps/documentation/javascript/...
https://en.wikipedia.org/wiki/Dymaxion_map#/media/File:Dymax...
Unless you're a hipster nerd trying hard to seem sophisticated. In that case, fashion is everything.
Now I wish we did not accepted that fast the lens-flares, but hey - my kid loves them.