What is net art? Since the beginning of the net itself, there has been an intense discussion about this question. You will find definitions everywhere on the net, and even if there is some agreement, the definitions vary. Let us begin with just four of them, with accompanying examples.
The very strict definition is this: net art is art that cannot be experienced in any other medium or in any other way than by means of the network. This means that being online is a defining criterion, because the art project, for instance, changes by means of its very presence on the web. A good example would be Mark Napier's projects Digital Landfill, Shredder, RIOT, and p-Soup. They explore such things as interactivity, sometimes even multi-user interactivity, the availability to everyone on the net, and the connectedness of Napier's projects to the entire network (1). This is in a way true net art, since these projects capture aspects that seem characteristic of and exclusive to the net.
Taking a slightly different point of view, however, we might come to consider other aspects of net art more important: for instance the way we experience it. Contrary to the way in which we usually experience visual art, net art makes private viewing possible. As David Ross has noted (in a text attempting to establish "21 Distinctive Qualities of Net.Art"), there is often a high degree of intimacy between the user and the art on the web. We can view it, and use it, in our home. The interaction is individualized (though not always). Artists like Entropy8Zuper! have constructed an intimate, emotional space on the web that deals with such old-fashioned themes as love and faith, and here we are not talking about sex among machines or cyborgs, but love connecting two human beings. It is interactive but on some levels more like "cinema" than net art in the previously defined sense (2). And it is brought to you every Thursday night at midnight, when the two artists perform live on the web.
Then there is telepresence, or telerobotics, an equally interesting tendency in net based art. Telepresence art usually enables the user to control robotic machinery via the net, thus performing actions in a far away physical space and with physical force that is often simulated for the user in some way through an interface. The simple version is the various web cams we find on the net, though this technology is hardly art in itself, rather it is the use that is made of the technology that makes a project interesting. Ken Goldberg's projects explore not only (multi-user) telerobotic possibilities, but also questions the actual technology and its effects on our conceptions of the web.
And finally, the very loose definition: net art is art that deals with "the net" and all that the net is about (chat, economics, distribution technology, copyrights, browsers, cookies, big-time corporate mergers, etc.), regardless of medium. In this sense William Gibson's novels are net art.
Returning to the strict definition of net art - art that only exists in its fullness on and by means of the net -, we might be able to make sense of the differences between the terms "net art", "web art", "online art", and "net.art" - four terms that tend to be used without much distinction. But there are slight nuances between them. It makes sense to use net art as the umbrella term covering the three other terms, the net being the actual computers linked together in a network.
Even if we use the words "net" and "web interchangeably, the web is a somewhat specific concept: the world wide web is a specific kind of net, namely what we see when we use the browsers Netscape and Explorer. The web makes use of a specific protocol for interpreting data, namely http (hyper text transfer protocol). By comparison we could speak of "telnet art", telnet being the previously used protocol, alongside "http art" or, as we usually say: web art. Net art would then be the umbrella term of these two protocol specific kinds of net art.
The term "online art" in many ways corresponds to the strict definition of net art: art that can or should only be experienced online. Here we have the question of whether the term net art is appropriate if a piece of net art for some reason - such as hardware problems or slow connection speed - is experienced offline. This is impossible in some cases, such as Napier's projects, because the work dynamically makes use of other web sites (3). In a way there are two kinds of "online art": art that is only there on the net, or art that is always there on the net - "only" being the stricter criterion since it tends to rule out telerobotics and web cast performances which may have an additionally important offline dimension. And, again, not all net art is always present on the net, and yet it would be wrong to disqualify it as net art, since it may indeed fullfil other criteria that an "always online" project does not.
Where online art ceases, net art does not stop. "Art distributed via the net" is a definition that does not necessarily entail that the art is actually located, stored or experienced online, on the net, but rather passes through it with the speed of, for instance, an email. Email art, the electronic equivalent of 1960s mail art, is sent via the web but not necessarily experienced there, and not necessarily accessible to every user of the web. Being point-to-point communication it also involves a pre-defined network of recipients. Quite a few net art projects, from Heath Bunting's early "Kings x phone in" (encouraging people to call the many public phones around London's King's Cross at a specific time) to rtMark's various activities, take place off the web, but are organized via the net.
Finally, as regards the dot in net.art, this demands a special explanation, according to some "historians" of net art (a paradoxical term, perhaps, for a person who researches art that has existed for only about six years, but remember that time on the internet is not equivalent to time offline). According to Rachel Greene, for instance (4), the term net.art has a particular use, it describes a more or less specific phase in the art of the internet. The term came about by accident. It was the result of a data conversion error: an email sent to the Slovenian artist Vuk Cosic was scrambled and the only intelligible information that remained was the "net.art". This etymology of "net.art" is generally accepted, and it refers to the kind of low-bandwidth, html based projects developed by the early pioneers of art on the net, such as the Slovenian Cosic, the Russian Alexei Shulgin, the British Heath Bunting, and the Dutch Joan Hemskirk and Dirk Paemans (JoDi).