Geek culture is not one culture, per se, but rather an affiliation of subcultures. As with any subculture, the internet has become a haven for these groups to show their appreciation, and many do so in the form of webcomics. While I feel a post on webcomics in general may be forthcoming, but with this highlight, I felt the comment about culture was apt as Darken is essentially based in Dungeons and Dragons.
Written and drawn by Kate Ashwin, Darken is in interesting study in anti-heroism and anti-villainy, as the entire main cast is more concerned with their scheming than they are about morality and loyalty. To call it character driven would downplay the well-placed (and paced) action, but the interactions between the characters and their ultimate goals are what drive the reader.
The art is smooth and expressive, with some slight Japanese influence, and the coloring, when used, contributes to the mood and energy of the scene. Very rarely is it possible to confuse characters, though there are clearly some "basic" faces at use.
You don't have to know D&D, but it certainly speeds things up for new readers. Regardless, Darken uses a mixture of action, humor, strong characters, and good plotting to make a very worthwhile read.