Just about everybody on the planet has heard about the open-source operating system called Linux. Heck you can even talk to her grandmother and she's heard about. But funny enough it's almost like folklore to the common person. Everybody's heard about but nobody really knows anything about it or is even seen it. I was once joking that Linux is a lot like the Sasquatch. It's an elusive beast that seems to not be taken serious by anybody but is been taken very seriously by many Fortune 500 companies.
Let me take a second to explain myself. I personally use Linux within my business for many years. One of the main reasons I did was not to save money but to provide flexibility to my business. I've nothing against commercial corporate systems but sometimes I find that this open-source offering system augments those other systems very well. For example when building a server for a small company I find that Linux fits the bill at times much better than Windows server does.
Also for web development I find that Linux is the platform you want to develop on. It's very robust and very secure. It has the benefit of many years of its UNIX roots. Whereas other operating systems are playing catch-up. I've worked with many companies large and small have used Linux to run their web-based applications within the company and to the outside public. You can service more clients, faster and better. Plus there's a large development community that has probably encountered every problem that you may encounter on your server. Because it's open source most of the information is also open-source.
If you're interested in using Linux or introducing it to your clients if you are a computer person I'm going to give you simple recommendation. Do not try to sell Linux as Linux. Sell a solution like a low-cost file and data backup server. Sell its benefits not its name. Another unfortunate thing that has occurred to the general public when it comes to Linux is the fact that many people do not take this offering system seriously. Many think it's just a toy. Whether you believe it or not this is one serious operating system. It's extremely robust. As a side note it's important to note that it is so robust that it can run for years without a reboot. So instead of trying to defend the Linux name simply install a solution based upon Linux and let them ask you what it is after their very happy with what you've done. When they discover that their business runs on Linux you already have made them a convert. In other words you've shown them the Sasquatch!