Most of the Web is text, and publishing text works that you wrote is possible in several ways:
Wikis such as the Wikipedia and friends.
One can set up a web site for his textual works, or have the PDFs downloadable via BitTorrent.
Weblogs and blog-comments are an increasingly popular way of publishing content online. Many blog services such as LiveJournal, or Blogger will publish your blogs free of charge, as will many community web sites.
Several writing or artist communities like MySpace and Writing.com accept submissions to publicise one's artwork.