Different people ascribe different interpretations to the term Open Source depending on which side of the divide they stand. However, one thing that remains certain is that everybody stands to benefit from Open Source and thus must necessarily support its spread. These are my reasons for believing firmly so
Open Source Software guarantees quality closed source software
It is very ironic but true. Without enormous pressure from mostly freely available and quality OSS, most closed source software would have just been junk. For instance, without pressure and competition from Linux, Windows 7 would not have been such a polished and nice software. OSS keeps closed source software developers on their toes in the knowledge that there is always some alternative available to users should they get it wrong.
Open Source Software reduces cost
Imagine your company in need of a particular software that is not available in the form it wants but there are others out there it can tweak to suit its needs. In this case, your company has two options, either build from scratch (which can be very expensive and time consuming) or grab the source code of an existing software and tweak it to their taste. Which would you prefer if you were the CFO?
Open Source Software fosters innovation
I actually find it very ironic that Bill Gates stood on the shoulders of giants to start Microsoft. With OSS, standing on the shoulders of giants to innovate is common place and encouraged. Take Ubuntu as an example. Shuttleworth has actually built on Debian what is indisputably the most popular alternative to Windows. Rather than spend an eternity starting from scratch, you can legally build on the works of others to add even more value than the original work. Society, at the end of the day, becomes the beneficiary of all innovations.
Open Source Software creates employment
Contrary to the arguments being advanced by firms like Microsoft, OS does not cause unemployment but rather helps to create employment. The job cuts that such companies have made were not as a result of OSS but rather a plethora of factors. If you are a programmer, which scenario would you probably like
a)A situation where you can actually grab the code of some software, add your own stuff and sell it as long as you respect the license you inherited from the original software
b)You do not have the right to do anything with any software whatsoever. Only the original company can tamper with their stuff. Which scenario will in the long run create more employment?
Open Source Software guarantees continuity
Imagine waking up tomorrow to the news that your corporate CRM software is no longer going to be continued. The firm behind it has decided to discontinue due to lack of demand and is also not going to give out the source code. What then happens to the massive investment your company has made in the deployment of the software?
Your only option would be to start from scratch with another one. This I doubt, will ever happen with Open Source Software. One developer stops a project, and another can freely and happily take over. Saving people the hassle of starting from scratch. Firefox is a great example of this point. Netscape died, but was reincarnated as Firefox. Today, it is the second most user browser out there. How is that for continuity?
There are more reasons why you now more than ever need to support and respect Open Source Software. You may choose not to use it for the sake of personal preference, but I think it deserves some respect and support from all and sundry if the future of the software industry is to be guaranteed.