The benefits of being open
Many companies and developers open their web applications, using a combination of APIs and RSS
feeds, in order to create a platform upon which mashup developers can thrive. Depending on the web
application, the reasons for this can be very different.
Innovation is encouraged
If you refer to the quote from Vint Cert earlier in this chapter, you can see that Google recognizes that
it does not hold a monopoly on creativity. Many developers out there will, given the chance, find
novel uses for data or functionality that the original programmers of an application may never have
considered. An API gives programmers the tools to experiment and create new applications.
In some cases, this creative output can be fed back into the research and development process, stimulating
new ideas and influencing the overall product direction. These ideas may be totally unexpected—
I doubt that anyone in the Chicago Police Department anticipated seeing police reports
plotted onto a Google Map!—and ultimately add considerable value to the data.
As a mashup developer, a lot of the fun lies in the ability to take different sets of data and create new
views of that data. This could potentially add value; for example, by plotting information on a map,
you add context that would otherwise be missing. Alternatively, combining data could ultimately provide
a form of creative expression and entertainment.
Following on from innovation, an API allows you to extend the functionality of a given web application,
potentially in areas that might not be of interest to the application developers themselves but often are
desired by a subset of the user base. For example, Housing Maps (http://www.housingmaps.com)
extends the functionality of Craigslist, allowing classified advertisements to be viewed on a map.