LimeSurvey (formerly PHPSurveyor) is a Web
application that interacts with MySQL, MSSQL, or
Postgres to develop surveys, publish surveys, and
collect responses to surveys. Once a survey has
been created, data can be inserted into the survey
either by a "pretty" public screen which presents
each question one at a time, or by a quick and
nasty data entry screen. It includes the capacity
to generate individualized "tokens", so that
invitations can be issued to participants. It also
has the capacity to set conditions on whether
questions will display (branching), numerous
question types, and a basic statistics function.