I am looking to build a "decision tree" survey tool, and would like to see if there are any tools like that already out there?
That is, a "decision tree" survey is a type of survey where your answer on question 1 defines what the next question will be, and so on. Kinda like those "choose your own adventure" books that we all used to read in middle school.
If you know of any such tools please let me know, I need to make a survey of about 100 inter-dependent questions.
As others have noted, what you're asking for in not unusual - but for the love of $deity$, please consider the people you expect to participate in this survey. So many questions will likely lead to a poor completion rate or poor quality of response. If not both.
Even forms on Google Docs have this capability, and to be honest I'd be surprised if any commercial tool lacks it. Certainly Surveymonkey and QuestionPro are right there.
What kind of logic is available, and to what extent you can embed information depending on previous answers varies a lot platform to platform. There are very specialist tools out there for 'big bucks' consumer research that are either expensive (they cost $$$), or exclusive (you can't buy use of the platform directly) and cover more complex paths and models of user interaction.