In a recent interview with the Financial Times, Oracle helmsman Larry Ellison said that he wanted to sell a complete software stack (with an operating system and applications), just like Microsoft. It's the new notion of packaged software--one stop shopping for enterprises. This kind of thinking is an extension of Ellison's notion that enterprises want simplification (such as a single database of record), even in a more loosely coupled services-oriented world, and that 'best of breed' isn't good enough to trump a packaged, pre-certified all-in-one solutions.
This kind of thinking is also behind Oracle's consolidation strategy--buying competitors with market share, tweaking little MySQL, SAP, IBM and Microsoft--and is morphing into a comprehensive Oracle operating system/middleware/database/applications stack, even if it means acquiring Novell or even Red Hat/JBoss. Of course, there isn't any reason Oracle couldn't continue to bundle Red Hat or SUSE Linux, but that would leave competitors standing, and Oracle's stategy has been to annex competitors in spaces it wants to 'commoditize.'
When Oracle Fusion ships, maybe in 2008, you can expect to get an appliance that has everything from the bottom to the top of the software stack, certified, sealed and delivered on premises or as a hosted service. As Oracle and its various competitors know (IBM, Sun, SAP, Microsoft, etc.), the real profits are in maintenance (services/support). Most companies don't want to be locked into a single vendor--no matter is the software is open sourced--but if you are already running Oracle's database and applications it's not much of a step to throw in middleware and a Linux OS.
If Ellision is correct in how the enterprise software industry will mature, look for business models that focus on delivering services, not software licenses, and for IBM to turn WebSphere into a more complete stack by acquiring SAP and one of the Linux distros, unless they are content fueling Red Hat's growth and betting the Oracle's Fusion will flop...