The DataGrid offers the ability to build out your data in a grid format in an HTML table, which is the most common method due to the nature of PHP. However, the DataGrid offers many other ways of outputting the tabular data structure such as an Excel spreadsheet or an XML document.
To use a different renderer other than the HTML_Table renderer, you can specify the name of the renderer (e.g. 'CSV', 'Pager' or 'XML') as the first parameter of the fill(), getOutput(), and render() methods. Another possibility is to use setRenderer() method. The old way of using the third parameter of the constructor to define the renderer is deprecated since version 0.7.0.
A list with the currently available renderers can be found on the overview page.