((Work in progress. Help greatly appreciated.))
When a website is personified, it is given a human form, a personality, or both. The personality and appearance given to the website is often derivative of the stereotype for people who use the site itself. For example, the anthropormophized form of twitter is usually shown as very talkative, and in some cases, annoying. Some characters, such as that of Anon, can come to represent the site as a whole.
While anthropomorphism has been around for a long time, it was usually only done to animals or other living things since they were already identifiable as a form of life. However, the practice of anthropomorphizing inanimate objects, specifically programs, did not occur until much later on 2channel. In 2001, Shiitake-chan was made. She was an anthropomorphic interpretation of the Internet Explorer "Stop" button. Eventually, other aspects of internet browsing were given "Moe" forms, most noticeably other web browsers.
Around the same time, deviantArt was holding a contest to find a mascot for their website. The winner of the contest, a user by the name of "switched" won the contest with his submission of "Fella", who was inspired solely on the idea that people on deviantArt should be as devious as the site's name implies. Fella was different from other website mascots because he had a distinct personality. He became more than just deviantArt's mascot, he became its face.
With both characters spreading around the web, both west and east had their own idea of what an anthropomorphic website was like. Japan and Korea made their websites with an anime feel to them, while the Americas and Europe were giving mascots more human-like personalities.
In 2003, the website, "Go-Gaia" was made, which would later be known as "Gaia Online". It was a forum-based community that was known most for the customizable avatars that visitors could dress up with outfits bought using gold received from interacting with other users. People began to create "avatar art". This practice, along with Gaia Online's interesting storyline, made the Gaia avatars the first widely drawn website characters.
When depicted in artwork, websites are usually drawn in an anime style, leading to the creation of Moe characters representing the site itself. Generally, informational websites, such as Wikipedia or TVTropes, are drawn as girls, while most social network sites, such as facebook or myspace, are depicted as men. It is not unusual, though, for a website to have three commonly used anime interpretations. If the website already has a mascot, such as deviantArt or reddit, an anthropormorphized version of it is sometimes made as opposed to making one of the site.
Website Mascots and Icons
Some websites have a very familiar mascot or logo. In this case the icon is given a personality, much like in the Supernews! episode "Social Networking Wars", which depicts Friendster, facebook, myspace, and Second Life. In the episode, the four different social networks are vying for the attention of a person, hoping for some log-in time. In the video, the different icons have been given personalities that match that of the stereotypical user of their site, or are just a complete exaggeration of what the site is about.
Websites that do not have a set mascot will sometimes have one chosen out by its users. Twitter's Fail Whale and deviantArt's Fella are examples of this.
The figure that commonly represents 4chan is known as "Anon", which is a green, no-faced person wearing a suit and tie. Anon is a special case since its design actually doesn't draw any inspiration from the site it represents. It is not just the unofficial mascot for 4chan, but it also represents the users of 4chan as a whole.
Spread and Usage
In spring of 2009, deviantArt user "elontirien" did artwork depicting websites as people inspired by his friend's short story collection called, "Internet University". Due to deviantArt's "Share This" function, the image spread to the social networks it depicted very quickly, causing people to try and make human versions of their favorite sites that were not depicted in elontirien's original drawing.
In November of 2010, 4chan's /b/ board did a raid on tumblr that ultimately ended up in the pairing of two sites together. After popularity of "4chumblr" grew on both sites, a rise in anthropomorphizing websites grew as well, most noticeably on tumblr, where the original 4chumblr drawing was posted. It has become a recent trend to make 4koma-style comics where tumblr-tan and Anon are interacting with other websites.