Deep Survey is a module which aims to turn Drupal into a market and social research surveying tool. It allows privileged users to add surveys to a site. These surveys consist of questions which then in turn consist of answer lists - both of these are separate content types. Other Drupal users may complete the surveys, being asked one question after another and responding via the answer lists. It is possible to have the user skip one or more questions based upon their responses to earlier questions.
The data collected may be downloaded from Drupal in csv format.
The current Drupal 6 version is "feature complete" but will still be provided with bug fixes if necessary. Once a Drupal 7 version has been completed the ability to loop through the same question as well as alter the text and responses dynamically (filters and substitutions) will be added.
A manual is available here.