The open-source concept was popularized through GNU and the GPL, and it has spread ever since, in an increasingly rapid manner. The open-source OS, Linux, has been growing in users exponentially over the last few years, and while it still has a ways to go before it can challenge Microsoft or Apple, it has become a viable and even desirable alternative for many.
Open-source alternatives have been growing in number and breadth: from office software to financial software to web and desktop utilities to games, just about any software you can think of has an open-source alternative. And in many cases, the open-source version is better.
Now consider this: the open-source concept doesn’t have to just apply to software. It can apply to anything in life, any area where information is currently in the hands of few instead of many, any area where a few people control the production and distribution and improvement of a product or service or entity.