LWAS is an app engine specialized for data-centric apps. Taken very lightly it's a replacement for improper databases kept in spreadsheet files (or just the file system) that many small business, teams and individuals have. Over the years LWAS has been inspired by major content platforms (drupal, wordpress) and it's aiming to be a platform rather than app for data rather than content.

Sure content is data but in any other platform is a kind of data, with a required structure (think of a node or an article database structure) and a required set of features. In LWAS there's no required structure for content, that is the content can have any structure. Actually in LWAS any data is content powered by a set of features to easily define the workflow to produce, manage and consume the data.

Documentation for those building LWAS apps is in the wiki

Some docs explaining the concept can be found at codeplex

There's a supported LWAS app template here