Commercial support is a very common form for marketing Free and Open Source Software. The end user does not buy the software as there is no licensing fee or artificial copy protection whatsoever. Instead the software is usually freely available for download, but without any warranty or support. In business enviroments where reliability is critical and breakdowns costs money, service providers with skilled developers jump in the gap. This can be hotlines for end users, contract works like programming extensions to existing software or even a complete all-in-one package which is sold as a payable subscription for the maintenance costs.
- All the ressources are put in adapting the software to the customers special needs instead of being put in general licensing fees.
- There is a market with a lot of variety because everyone can hire specialists, change to another service contractor, instead of one monoplist that can only provide services.
- Red Hat sells a supported enterprise Linux variant, RHEL
- Canonical the commercial sponsor of Ubuntu Linux, provides support independent of their distribution
- Content Management Systems (CMS) that are freely available can be customized, hosted and supported by several independent service contractors. Popular open source CMS common in business scenarios are Joomla or Typo3  .