The first thing I need to point out, and indeed I do, like a fish needs water, is that art is purely a personal thing. There is no single definition of art, more like billions of them, and people believing otherwise are nothing but close[dt]-minded fascists. It's not only that artistic values vary from one culture another, but between two given individuals, even if they suckled from the same breast.
That being said, what follows is my view of art; mine and mine only, and I find no pleasure whatsoever in knowing that others may or may not share it.
The word "art" comes from the latin "ars", which means "skill", or "craft", and is closely related to "arma", which refers to joining, fitting together etc. So the roots of art lie in making tools, or using tools to make other (useful) objects and such similar activities. Contrary to popular belief, for a long while, art involved not only aesthetics, but also practical aspects: a good carriage was "a fine piece of art" not only because it looked good, but also because it served its purpose well and because it was the result of weeks, maybe months of hard work.
In time, the meaning of the term shifted to what is nowadays known as "fine art", that is, works that are highly polished and refined by the hands and minds of the greatest masters of a particular field. Art is therefore not simply craft, but also the best there is.
A second shift led to the view that art is not only the best, but it is also that which transmits emotions. This definition is hardly quantifiable, since subjective experience can, as I previously mentioned, vary greatly from one person to another, and thus art becomes purely a matter of taste and preference. So what is, in my opinion, art? It is two things.
Firstly, it's a product of mind, hands and whatever else it is that created it. Art itself doesn't involve the process of creation and it has nothing to do with the person that created it. Trying to find the meaning of a piece of art in its creator is nothing more than egomania and mindless adulation. Surely, creators deserve praise and criticism for their art, but in the end it's the livened piece, not its author, who speaks. Furthermore, once it's created, the piece becomes completely separated from the creator, becoming subject to its consumers' scrutiny.
This also implies that aspects related to the process of creation, for example the tools used, are completely irrelevant from the point of view of art, since consumers can in few cases judge the tools themselves. Besides, including creation into art would exclude non-humans from the artistic process, which is obviously wrong, since nature is one of the greatest artists in history.
Secondly, art is that which leads to the "improvement" of mankind, whatever this so-called "improvement" might be. Electronic circuits, and computers in particular, are clearly art. The Internet is an incredible piece of art, not only due to the fact that it's bigger than what any single human could have ever achieved. These are simply "the best" and they convey the emotion of awe, which makes them fall into the standard definition of art. Engineering is an art and any attempt of the humanities to prove otherwise are not only misguided, but also malicious in nature.
These two definitions are interesting due to the fact that they include computers as creators of art. It's absurd to try and find "personality" in a computer-generated work of art; it is also absurd to say that that which is generated by a computer is not art, even though it can compete in refinement, maybe even surpass the equivalent created by a human.
However, my view does not and cannot integrate some concepts into the definition. For example, it doesn't allow for intellectual property. Since art only depends on the final product, then near-perfect copies have the potential to be as valuable as the original. Since art can be created by machines, art can be copied by machines. This, by the way, is something which upsets copyright holders, a thought which is a good starting point for another, which I may discuss at another time.