Dada Mail is a few things:
Dada Mail is a general purpose mailing list manager, targeted to be used for small to medium organizations such as businesses, non-profit organizations and personal sites. A Mailing List Manager is a program that handles the subscriptions of a mailing list and in this case also sends out mailing list messages - emails that are received by everyone that is subscribed to the mailing list.
The goal in this perspective of Dada Mail is to be able to be easily installed and useful by a web-savvy person. This person does not have to be a professional web designer/developer. It is also hoped that there is much breathing room for the program to grow with the needs and expectations of whatever organization it is to be used for.
Dada Mail is also a many-tiered art project. The initial goal was to see how far a self-taught, admittedly poor math student could take a computer program, written from scratch. The answer it seems, is very very far. The idea being played with is of a person taking on a role that doesn't seem to fit them well and flourishing. This wasn't acting, this was real life. Four Years is a Long Time.
Dada Mail is also used to question the idea on what a piece of software is and what it isn't, making definitions such as "name", "function", "purpose", slippery. The creator of Dada Mail, Justin Simoni, has many more credentials as an Artist, attending the Rocky Mountain College of Art and Design as a senior in their Drawing and Painting program, than he does as a Software Engineer, of which credentials he has none, except the time he has spent with projects, like Dada Mail.
Since Justin is an Artist, he has decided that Dada Mail is an Art Object. This sort of art object is called a Ready Made, the term itself invented by Marcel Duchamp. Duchamp was one of the original Practitioners of the (anti-)art movement, Dada. So now you see the link between name and object.
The twist to all this is that Justin created Dada Mail from scratch and took many years to develop it to its current state. This makes Dada Mail dissimilar to a Duchamp-like Readymade, where an object, like the famous Fountain (a urinal) was designed and built by somebody else, perhaps an entire group or company, and then chosen as an Art Object by an Artist.
Justin has both designed, built and chosen the object, in this case, Dada Mail. The Object (Dada Mail) inherents all the beauty of its contemporary world which it is grounded in (i.e., it couldn't have been made 20 years ago or 20 years in the future) and also literally communicates ideas on its own with the various email messages it helps in sending out. As far as Justin is concerned, it is now permanently placed into the White Cube of the Art world for critique.
For the most part, Justin has no control on what these email messages actually are and thus loses control over what actually is communicated even though he facilitates this communication. This is the inverse of what you would expect an art piece, for example a painting, to provide: a painting provides the content to communicate; Dada Mail provides everything but the content.
Justin has found himself in a unique position, having a very mature and loved computer program and wondering what to do with it - what its purpose to him was, since he is an Artist. By labeling Dada mail as an Art Object and specifically a Worldwide Art Installation, Justin finds Dada Mail very important.
This Art Project was renamed Dada Mail in November of 2003. It was, beginning in December of 1999, called Mojo Mail. But, for legal reasons the name was dropped. A company that has a very similar product named MOJO Mail seem to think that this project infringed on their Trademark.
In response to this, Justin renamed the program, not wanting to get into a legal debacle. The short of it, from Justin, "They have lawyers, I sleep on a couch in a basement apartment that doesn't have working heat." He also officially deemed it as an Art Object, not a Software Project. Art Objects have "titles", not "names", of which different Art Objects can have the same "titles". For example, "Untitled", "Pieta", "Virgin", "Fountain". The medium of Dada Mail is a computer program. As far as Justin knows, you can not Trademark the title of a piece of Artwork. Justin would at least like you to think of this whole idea in the perspective that he has given it to you and hopefully you think of it as totally absurd. Perfect.