Icon Source: rainraven
It is Sai calling someone bro as he did in G Gundam’s dubs. Dreamwidth is a fork of LiveJournal by former LiveJournal staff. There are many forks, but Dreamwidth is the most popular with their users linking between the two sites. Pixiv source no longer exists.

Icon Source: reccessional
Fire Candy has amazing character art with a very wonderful rough style. Above is “manga coloring” and not official art or from a cover.

Icon Source: ukemilk
Original Source: Nico Nico Douga
The icon originated from a Nico Nico Douga video with the Vocaloid Kagamine twins Rin and Len.

Icon Source: kazimierzi
Aventura was a formally licensed and published manga by Del Rey before Kodansha took over their manga publishing. It sported some of the most dreamy and excessive character (especially hair) detail. Safe to say Del Rey had much more interesting manga choices with Q Ko-chan, Alive: The Final Evolution, and Yozakura Quartet. Kodansha’s US division is far too timid and does not bother much with manga outside big hits.

Icon Source: mensenhater
Original Source: momocan.egoism.jp (a little NSFW)
Most of my favorite avatars or what LiveJournal calls icons have action, posing, or a bit of emotion. Just a character’s face is bland and not very creative. It is Ken cross-dressing in what the blond Aigis android is known to wear in Persona 3.

LiveJournal is a giant from a long ago era where people created communities of posting user avatars. Users had the ability to upload more than one icon (avatar) and choose which they wish to use when commenting or publishing a blog entry. In a way the site is very much like WordPress.com in where it is a network of blogs, but community and networking is much more stressed. Users created communities for anyone to post entries to and used them for massive image heavy posts with often a hundred icons. The community may not be Facebook, but it remains active and worth the membership.

Drawr.net is a Japanese artist community for creating and sharing illustrations and oekaki doodles. It sports a Flash web editor for making your own works on the site itself or to reply to images and people in image form. Each image has the process of the drawing saved where you can watch line by line of the image being created. The Pixiv owned site also has RSS feeds for all its members, new images, and the most recent popular. Unlike Pixiv you can browse the site freely without registration, but registration does mean having a Pixiv account. People and images can be bookmarked, as there isn’t a tagging or search system.

Genji
Works from Genji generally have a gang of these four or so characters and often times characters from GeGeGe no Kitaro and Akuma-kun. Works have a very rough appearance, layered hair, and well-chosen colors. Often times there will be subtle or not so subtle references to indie music or bands.
drawr | Pixiv | Tegaki | Site

t
Another artist with a flawless sense of style in character designs. Lots of abstract and fantasy imagery and the Vocaloid twins Rin and Len with consistent use of soft colors. Most works keep it simple and limit the number of different colors.
drawr | FC2 | Twitter | Pixiv

spring-buffalo
Akuma-kun and GeGeGe no Kitaro characters set in much darker, violent, or suggestive themes. Many of the drawr images are sets that can be viewed together when you try select one of the images and those sets can be often times very dramatic.
drawr | FC2 | Pixiv