Decision Tree plugin is the only plugin we know of where you can easily build a decision tree (DT). It’s intuitive to use with our in DT editor interface. You can quickly build up your questions and map them to the correct answers.
This will protect the user or admin facing wordpress pages. Separate login and passwords can be setup for each. This isn’t anything fancy, not super secure, just basic and easy. It is called simple after all.
Do you have a blog that really only want ready by humans? Do think that robots should never be able to read your blog, even if they ignore your robots.txt? The 404er will make every public page of your blog return a 404 instead of the normal 200.