In many ways, learning how to write and edit well, for print or broadcast, will help you write and edit better, for online media. There are differences, of course, but many of the most basic skills and techniques are the same. There's much more at stake than simply attracting an audience. I think it all comes back to the goals of the site. For visual art, there is always the issue of how faithfully the work will be displayed on the Web.
Different browsers use different color palettes, and resolution can be an issue also.
Now, on the other hand, it's possible that the paramount goal of an art site is to create an experience of puzzlement. However, don't expect this kind of site to draw a huge audience, unless it is somehow entertaining or sensationalistic. At the most basic level, this zine can help increase their content awareness . Also, it offers insight into how to evaluate a site's content, and how to create great content for their own projects. Also, more and more Web developers and designers are working with writers and editors on Web projects.