A few days ago, a colleague pointed out to me that "simplicity" is not a feature. His reasoning behind this was that simplicity means different things for different persons, so simplicity can mean anything inside of a range of things.
I don't agree with his statement at all, and I actually think that simplicity is the only feature any program can have. In the widest sense, all that computers do is provide a given task in a simpler way, usually making that task faster and more accessible to different groups of users. Some of the times, making a task simpler makes the task possible in the first place.
Even at the beginning, one of the first instances of a computer was the famous difference engine, invented by Charles Babbage. Its sole purpose? Computing tables of logarithms in a quick and reliable way. In other words: making finding a given logarithm simpler for the user. Note that the logarithm tables themselves are a way of making that task simpler in the first place.
After the difference engine came programmable looms by J. M. Jaquard, which made the production of complicated, patterned fabrics simpler.
Later, "real" programmable computers were invented by Konrad Zuse in Germany and von Neuman, Turing and others in Great Britain. Their use cases? Solving linear equations, doing the necessary computations to reverse code ciphers and computing ballistic tables. All of which make the underlying task simpler for the user. They also made these tasks a lot quicker and a lot more reliable, but these are merely side effects of making the tasks simpler for the user.
Mainframes: Making it simpler to do complex calculations of any kind for many users.
Home computers: Making it simpler to do complex calculations of any kind on your own.
The internet: Making it simpler to retrieve information that is stored in different places.
Email: Making it simpler to contact people that are not immediately available (i.e. making it simpler to send letters).
Even "modern" services and gadgets like Google (making it simpler to find some websites that store information you might be interested in), Facebook (making it simpler to have a homepage, share photos and see what others are doing), Twitter (making it simpler to tell everyone who's interested what you're doing) or Apple computers (making it simpler to use all the awesome stuff that nerds built for themselves) are built on that one guiding principle of simplicity.
Note that oftentimes, with simplicity come other benefits like scalability or even availability, which help adoption and development of even newer, even simpler products.
But the main thing that software, that technology does, is making stuff simple. I can't think of a single example of a product or service that is not making something simpler.
Shameless plug: I'm doing Bit Chest at the moment, which is built around being a simple and safe file archiving solution.