The name of this next web application says it all; LimeSurvey is indeed a web application that allows surveys to be conducted in an effective and efficient manner online. It was formerly known as PHPSurveyor and it is still a free, open-source web survey written in PHP.
LimeSurvey works with MySQL, PostgreSQL and Microsoft SQL Server. You can choose which database framework to use according to the scale of the survey, the resources you have access to or simply based on your budget.
Once installed, user can set up surveys immediately. Add questions through your LimeSurvey admin panel and define certain rules for the survey before putting it live for visitors to access. For instance, you can set the survey up so that each user can only complete the survey once.
LimeSurvey supports data processing as well. The information entered by visitors and respondents are grouped and processed accordingly. You can see a clear overview of the responses you get from the admin panel. You can also generate comprehensive reports, define custom parameters for each of them and have LimeSurvey perform statistical and graphical analysis on the fly.
It is difficult to find a web survey application that can match the functionalities offered by LimeSurvey.