People often ask us, "Why is SIL developing for Linux?" Sometimes they ask about Mac too.
The main SIL use of Macs is in Asia, or anywhere else that scripts have been an issue over the past couple of decades. They are not found in every SIL location, but they are in use, and so we need to provide software for their language projects.
Regarding Linux, we are targeting a future user base that we and our administration believe will soon exist. In software development, you need to be working 1-2 years ahead of the curve in order to be anywhere near current when you actually release your software. The most obvious future Linux users are mother-tongue translators (MTTs), since Linux greatly reduces the cost of setting up a computer system for them, mostly due to the avoidance of costly software licensing fees. Although SIL members can get incredible discounts from Microsoft, this often doesn't apply to MTTs and there are issues with us "lending" them our specially-licensed software.
We believe that Linux has a lot to offer expat translators, too. Although cost is not such a factor for them, the stability and security of Linux are big advantages, and the range of applications usable by an expat greatly increases when they can try them out and then start using them at no cost. We also feel that it sends a very bad message to nationals when we choose not to use the computer systems that we are recommending they use. This only perpetuates the feeling that we are giving them second-best.