While I'm certainly not an efficiency expert, I also don't like to waste a lot of time deciding what to wear or how to accessorize. Since bedrooms usually serve as both a place to sleep and a place to dress, it makes a lot of sense to decorate the walls in a functional manner as well.
With not a lot of space in my closet, I decided it would be a pretty decision to store half of my often-worn hat collection on the walls where I dress each morning. In addition to the wall display style of organizing, I also have a small collection of hat boxes in which I store out-of-season hats on shelves in my closet. But as a visually oriented person, it's very helpful to see options out in the open when selecting what to wear each day. So, instead of keeping them pent up in boxes, they spend six months of the year in plain sight, or on top of my head.
To hang the hats, I simply used a level to mark spots where I then secured long nails to hang each one. In a pinch, it was an easy solution requiring supplies I already had in my possession. Not perfect, but certainly pretty!
Images: Amanda Johnson
Find Your Style: 20 Classic to Contemporary Kitchens to Add to Your Inspiration Board
Beth's Romantic & Retro Residence
Good Food to Share 
The Big Book of Small, Cool Spaces 
Apartment Therapy Presents 
The Eight-Step Home Cure 
Shaw's Original Fir...
10 Ways to Put a Muffin Pan to Good Use (Other Than Making Muffins!)
How To Cook Tender, Chewy Wheat Berries on the Stovetop
my oh my... As a hat person (you either you are or you aren't) I think this idea is pretty cool!
I've done something similar.
These long-shanked push pins are easy to place and remove. I'm hoping that the holes will be near invisible when it comes time to move from this rental:
http://www.whittemoredurgin.com/7340pushpins.html
looks great.
When my great-grandmother downsized, I got a bunch of her old hats. I don't wear any of them, but I wanted to hang them on the wall like this as decor. My husband nixed the idea, but I plan to do it anyway in our next house.
I LOVE hats! I recently hung my favorite nine hats on my wall in a three by three pattern. I was tired of them getting crushed in my overstuffed closet! .
This is a beautiful way to display your hats, but may I offer a little warning? Those close to the window should be rotated out frequently. I kept a 1920's hat, that my grandmother wore in a wedding, on display in a bright room, and unfortunaely it faded quite markedly.
That is a great look and works well for hats you don't plan on wearing again.
Unfortunately, it is very, very bad for hats to be stored that way.
The hats will become misshapen because of the weight of the hat being on the band instead of the crown.
Sadly, I know this from personal experience. I am a hat person (I have many dozens of hats) and I inadvertently damaged some this way. I was able to reblock them but they were never really the same again.
If the hats are purely decorative, then it's a look. But if you value the hats, then it's a pretty silly idea. Not only will this ruin the shape of the hat, hats also need to be protected from light, dust & humidity. That is the whole purpose of the hatbox.
I ruined many hats this way...
The hats get dusty! Not so pretty then.
As cute as this is, hats really need to be stored away from moisture, dust, and sunlight. If this was set up in a walk in closet then it could work.
i love this it's so beautiful! I love hats but unless it's winter I rarely wear them, yours are so fancy where do you wear them?
I wear these hats every day. Obviously only one at a time. :) There's no need to have an occassion to wear a hat. And while most people are surprised to see someone wearing an outfit complete with a hat, they usually make very nice comments and it seems to brighten even their day.
As far as damage, these get rotated out quite often. My hat collection is quite extensive, and I go through my hat boxes frequently to rotate out my collection.