While we're reviving old dead threads.........
Just watch out for "Abandonware" and "legally released" in the same sentence. Yes, many programmers have done this; but many more have *NOT*. In fact, the term "abandonware" is usually used to refer specifically to software that *hasn't* been "legally released" by its author. Once it has, it becomes "freeware". (Like iCab 2.9.9. It's not 'abandoned', it's just 'free' now.) The term abandonware is generally used when referring to non-free software that is so old and forgotten that the original author either can't be found to ask for permission, or has never given specific permission, but has not made an effort to block its distribution, either.
For example, old Apple OSes are not "abandonware" because either: A. Apple makes it available for free (6.0.8, 7.5.5,) or B. They block attempts to release (the oldest Mac systems, OS 9, etc.)