From Costume Fandom:
All Dressed Up with Some Place to Go! By Dr. John L. Flynn
For almost 50 years, costume fandom has had a consistent and widespread following with costumers markedly influencing science fiction writers, artists and the media. Costuming, as an innovative, three-dimensional art form, has probed and broken all limits of imagination in SF and fantasy. From the first Worldcon in 1939 to last year's Worldcon in Philadelphia, costume fandom has emerged as a robust and dynamic force within science-fiction fandom.
At the First World Science Fiction Convention in New York in 1939, a 22-year-old Forrest J Ackerman and his friend Myrtle R. Jones appeared in the first SF costumes among the 185 attendees. The future editor of Famous Monsters of Filmland was dressed as a rugged looking star pilot, and his female companion was adorned in a gown recreated from the classic 1933 film Things to Come. Both of them created quite a stir among the somber gathering of writers, artists and fen (plural of fan), and injected a fanciful, imaginary quality into the convention's overly serious nature.
Frederik Pohl, in his book The Way The Future Was, described the couple as "stylishly dressed in the fashions of the 25th century" but feared that they had started an ominous precedent. He was right! So successful were their costumes that the following year, about a dozen fans turned out in their own "scientifiction" apparel.
Now, over a half century later, costume fandom has come to represent a large segment of the hardcore genre audience. Artists like Kelly Freas, Wendy Pini and Tim Hildebrandt, authors like Julian May and L. Sprague de Camp, and fans by the hundreds dress regularly in costume. Groups, such as the U.K.‘s Knights of St. Fantomy, the Society for Creative Anachronism and the International Costumers' Guild, conduct business and ceremony in costume, and the masquerade has become the central event of most large conventions.
Costuming and Cosplay - What's the difference?
For many years fan costuming was confined to science-fiction and fantasy conventions, mostly in North America. Then, Nov Takahashi (from Studio Hard) coined the term "Cosplay" as a contraction of the English-language words "costume play". He was inspired by hall and masquerade costuming at the 1984 Los Angeles SF Worldcon, and his enthusiastic reports of it in Japanese SF magazines sparked the Japanese cosplay movement.
The idea took hold in the minds of the Japanese readers and they in turn adapted the idea by dressing as their favorite anime characters. In a matter of a few short years, fans began to dress up as characters at comic book and sci-fi events in Japan. Then in the mid-1990s, as anime, manga and all things related started to catch on in America, cosplay was reintroduced, this time on a much large scale. This has led to many North American cosplayers being totally unaware of their hobby's history, believing it was invented in Japan.
The fact of the matter is that the general approaches and attitudes towards costuming are very different in Japan and North America. North American costuming is still run primarily along the Worldcon model, in which people make their own costumes and compete at local fandom conventions. Original concepts and designs are welcomed and creativity is encouraged.
In Japan, for the most part, 'cosplay' is more about 'being' a pre-existing character, so the aim is to look as much like and act like the character as possible. To this end, there is not as much emphasis on making one's own costume, and there are not the same kinds of competitions as in NA. The aim is more to just have fun with your friends and have pictures taken. Cosplay is also more of a young women's hobby in Japan, whereas in NA costuming is practiced by people of all ages and walks of life.
Want to know more about Worldcon and Costume-con? Here are some galleries that show what kind of stuff you can see there!
Noreascon 4 (62nd Worldcon)