A computer software work is a work, and the form of this work is often the form of software. Give you the simplest example:
Painters draw pictures, and the pictures they draw are works.
If you make a software yourself (you can imagine yourself or several people making a software similar to QQ), then QQ software is a software work.
If your painting looks good, you can sell it for everyone to enjoy.
If the software you design is easy to use, you can also sell it for everyone to use.
Isn't QQ and Thunder that everyone uses every day just software at work?
You got it?