net.art refers to a group of artists who worked in the medium of Internet art from 1994. The main members of this movement are Vuk Ćosić, Jodi.org, Alexei Shulgin, Olia Lialina, and Heath Bunting (irational.org)...
The term "net.art" is also used as a synonym for net art or Internet art and covers a much wider range of artistic practices. In this wider definition, net.art means art that uses the Internet as its medium and that cannot be experienced in any other way. Often net.art has the Internet as (part of) its subject matter but this is certainly not required.
Internet art (often referred to as net art) is a form of digital artwork distributed via the Internet. This form of art has circumvented the traditional dominance of the gallery and museum system, delivering aesthetic experiences via the Internet. In many cases, the viewer is drawn into some kind of interaction with the work of art. Artists working in this manner are sometimes referred to as net artists.
Other references:
Internet Art by Rachel Greene
net-art.org