Apple's new Xcode 4 could portend new HTML5 development tools
This all happened before
The idea of Apple using its existing software to expand into new areas is nothing new. Apple filled a huge vacuum for native Mac OS X productivity tools with Keynote, purportedly designed in large measure to allow its chief executive Steve Jobs to create presentation slides.
The look and feel of Keynote was subsequently expanded with the Pages word processor and Numbers spreadsheet to deliver a suite of iWork apps. Apple just recently the suite ported to the iPad, where it now serves as the top selling productivity tools of what is now an iconically popular new tablet.
Apple has similarly built a suite of lifestyle apps in iLife, designed to create a digital hub for creating photos, movies, web pages and music designed to sell Macs. The company then reused the overall interface for its GarageBand music application to deliver Instruments (below), a development tool based on top of Sun's DTrace, a comprehensive dynamic tracing framework.
Instruments leveraged the time scrolling interface of GarageBand to make it graphically intuitive to monitor the performance of processes over time, their resource consumption, and so on.
A third application Apple created and reused was iTunes itself. While distributed for free, iTunes was financed by the popularity of the iPod. Apple's success in selling iPods resulted in liberal investment in iTunes, enabling the software to quickly outpace the company's other apps in sophistication and utility. The most notable contrast in good and bad software at Apple may have been iTunes versus the Finder.
By the time Apple shipped Mac OS X Leopard, the overall interface of iTunes was so refined that it made sense to simply reuse most of it to create a new Finder in order to replace the lagging cruft that had been lingering since the release of Panther. From the new Finder's device, places and search listings to Cover Flow icon browsing, the Leopard Finder was able to get a major refresh by simply reusing much of the word created for iTunes.
On page 3 of 3: Xcode for web content.