In Praise of Loopholes, simply put, is a great story and an example of fine writing you can only find online. (From our own shadowkeeper).
Paul Ford's Ftrain has a great piece on Micrsoft Word, writing, and the web. His stream-of-consciousness essay has hilarious nuggets like the "computer science axiom 'all software expands until it can send mail.'" There's a couple illustrations worth noting: the first looks like Word with all the tool bar icons enabled, and the other is Word's paperclip assistant interfering with an especially private moment. Great stuff.