Nick Carr, Marketing Director with Red Hat (www.redhat.com), says:

Open source technologies are not restricted to use by large enterprises, in fact open source software such as Linux has its roots in small systems. Linux systems can be used in pretty much any environment – classic small deployments would include network infrastructure systems, web servers, file/print servers, MySQL-based database applications, etc.

Open source applications are available to replace traditional SMB deployments, including email/calendaring, content management, CRM, etc.
And extensive middleware capabilities support application serving, portals and Java environments.

Perhaps the most pertinent information is that the cost of entry for open source software is very low. A lot of software is available for no cost, with support provided on an ad hoc basis by Internet communities. A good example being Red Hat’s Fedora distribution of Linux (see http://www.fedoraproject.org). These offerings provide a great way to get started. Of course, for a professionally supported environment it is necessary to use a commercial-strength product such as Red Hat Enterprise Linux, which is sold on a subscription basis. The rapid growth of Linux – it now accounts for approximately 30% of new servers, and continues to grow rapidly – is a testament to the success that customers are having with it. Deployments of open source software have a well-proven track record of saving customers time and money.

Virtualization, which is fully integrated into Red Hat’s products, enables customers extract the most from their hardware through consolidation, while running Microsoft and open source software at the same time on the same system. And open source software is essentially dominant in the rapidly growing cloud market, so in-house and cloud deployments can be highly compatible, allowing SMB customers a level of operational flexibility that has never been possible before.