A partial list of examples of this practice (sorted alphabetically): -
- Adobe Flex Builder - Eclipse
- Adobe Integrated Runtime - WebKit
- Apple Mac OS X - BSD
- Apple Safari - KHTML / WebKit
- Borland JBuilder - Eclipse
- Google Andriod - Linux / WebKit
- Google Chrome - WebKit
- Google Picasa (for Linux) - Gecko
- IBM Lotus Symphony - Eclipse / OpenOffice.org
- Red Hat Linux - Linux
- Zend Studio - Eclipse
- Catapult effect: Vendors such as Google, which otherwise would've taken months or maybe years to build (from scratch) feature-rich yet stable versions of their software products (in case of Google, these are Andriod, Chrome, Picasa for Linux, etc.), can now come out with refined and souped-up versions of open source software - in mere weeks. Time saving apart, potentially millions of dollars in development and testing is also saved. I would go as far as to say that open source software is a blessing for vendors such as Google - so while most of the evolutionary and maintenance work is done by third-parties, Google (and others) get to eat the fruit. The "lead", which vendors such as Adobe and Microsoft used to have over other vendors, matters less now in those areas where rival vendors have commercialized open source software. Imagine a vendor coming up with a slick photo-editing software, based on GIMP, which removes all the annoyances of GIMP.
- Customer concerns about support & services: Why are many enterprises and SMBs wary of adopting open source software? One of the major reasons is support & services. Commercialization of open source software mitigates this concern. Take Red Hat Linux, or CollabNet Subversion - these come with support & service options, just like those from vendors such as HP / Microsoft. And this largely eliminates a key barrier to adoption of open source software.
- The Long Tail: Yet another effect of commercialization of open source software is the development of software packages targeted at niche markets. These specialized versions of open source software (or standard versions used with a combination of paid plug-ins) appeal to users with specialized needs. Anyone familiar with The Long Tail should be able to grasp the meaning of what I'm trying to say. So using the same KHTML / WebKit code, different vendors have come up with software development tools that are "specialized" - Chrome, Epiphany, iCab, Midori, OmniWeb, Safari, etc.
In summary, commercialization of open source software poses a real, a serious threat to those vendors, which are hell bent on developing and selling proprietary software built from scratch. They call it reinventing the wheel.
P.S. I wrote this post in SRWare Iron browser (a fork of the open source Chromium browser, on which Google Chrome too is based)