And for the macintosh thing, The Mac OS is UNIX based. So Linux has nothing to do with Macintosh. And if software is for the Mac OS, it's for the Mac OS. If it's for Linux/Windows, it's for Linux/Windows. There is hybrid software you can buy, but it is hard to find.
I really don't think that Linux has spread to the point of being as functional as Win/Mac OS. But as it becomes more widely used, surely newer versions will be.
I would say that Linux is not suitable for everyone, yet. I feel that more tweaking is needed before just anyone can use it.