The Web is One Very Large Magazine, updated every split second. Too large actually to fit into a table of contents; nobody knows exactly what the magazine is about and what's on its pages. The Web is a magazine without filters and it's entirely up to the readers to find articles of interest to them in this vast billion page publication.
By describing the World Wide Web as a magazine, one immediately encounters the reasons why it is not: There is no editorial point of view. That's where the electronic magazine comes into play. It has been said before: the main problem of information technology is not the content, it's the context, or more precise, it's the way you filter content through contexts. Lost in an ocean of info, the browser looks for anchors. And the most precious thing a Web magazine can do is: provide a well structured and well argumented set of links to a well defined subject. It makes you come back.
Of course a Web based magazine provides its own content too. The difference with print is not only non linearity - print magazines are themselves to a great extent non linear media. The main difference is: multimedia. From the pages of an e-zine, you can play Real Audio music while you read and browse the rest. Short animations will pop up around the text and sometimes the text will flip its own pages, or change into an illustration, that changes into another illustration. And at all times you're able to choose between going deeper into the information or linking on, or out.
In this sense a web based magazine works as the WWW at large: at best it provides a great variety of material, that is connected in more than one way. The e-zines' interfaces mirror this: it is rather common for web magazines to provide three or four different ways of navigation. And the content itself may change in ways that a print magazine can't follow: a web magazine can be updated at any time, so the difference between 'issues' isn't that clear - they tend to gradually grow out of each other. And, more than in print magazines, the design of e-zines is the design of links between parts - the consistency is in the linking.
Like print magazines, most e-zines try to appeal to a specific audience. The graphic design of a magazine mirrors the lifestyles of the targeted group of readers. They have to be able to identify with the magazine and its editors. This is maybe even more important for web based magazines than for their printed counterparts who can check their readers' loyalty through subscriptions; The reader of an e-zine has to bookmark it. The more they can identify with the form and content, the more often they will come back to their anchor in the web.