Understanding a mobile device’s limitations and optimization of response time were two of the key recommendations the World Wide Web Consortium made in its “Mobile Web Application Best Practices” report.

In development since 2008 and published in December, this set of best practices specifically addressed mobile Web application development, “because [mobile development] is not really the future anymore; it’s today,” said François Daoust, mobile Web specialist at W3C.

The purpose of the document is to advise those just getting into mobile development and don’t know where to start or what’s important, he added. But the guidelines are not targeted solely at developers, the W3C said; interaction and graphic designers, site administrators, and tool developers are also encouraged to read it.

To Daoust, the most important points are understanding the data constraints of a mobile device and reducing the use of the network because data is not always free, he said. “Mobile Web developers have to assume the user is accessing data ‘on the go’ and may not always be connected to a wi-fi connection… On a wi-fi connection the data transfer is a lot faster, but it may not always be available or may cost an additional fee to connect to in a public place, such as a coffee shop. There is, eventually, a ‘real’ cost because mobile users do not all have flat rates, and cost can be around US$1 per 100KB.”

Increasing caching is one way to reduce reliance on the network, he said. Two recommendations to increase caching are fingerprinting resource references and caching AJAX data. According to the W3C, “a resource that is embedded within an application (an avatar, a style sheet, a script) that may change from time to time can still be flagged with a version number.”

Additionally, “Web applications exchange data on a dynamic basis, but this does not necessarily mean that the data itself is dynamic. Caching directives may be set for AJAX data, which is a quality that is often overlooked,” the W3C said.

Developed with the Mobile Web Best Practices Working Group (which includes AT&T, Deutsche Telekom, Google, Nokia and Opera Software), the best practices also address the importance of exploiting a mobile device’s capabilities to enhance the user experience, while understanding not all devices have the same capabilities.

“This means a developer should take advantage of touch-based screens, but still design for other forms of interaction,” Daoust said.