psiturk.org Secure Ad Server
Participants recruited via Mechanical Turk first interact with your task via ads. Ads are simply the digital version of hanging a poster or flyer around your university building in order to recruit participants. Technically, ads are snippets of HTML code that describe what your task is about and what you're offering for compensation. As a result, they are the front line for any subject recruitment online. It's easy to overlook the importance of a good ad, and making that ad visible to as many participants as possible.
.. seealso:: `Getting setup with psiturk.org <psiturk_org_setup.html>`__ Use of the Secure Ad Server requires an account on psiturk.org.
Ads, Amazon Mechanical Turk, and the External HIT type
Any task (or HIT) which you deploy on your own server is listed using the "external HIT" type (a special name that Amazon uses for tasks which are hosted on external webservers). For these types of tasks, ads show up in users' browsers as a HTML document. Due to recent changes in browser security, if your HTML is not encrypted and signed using an "official" SSL certificate (e.g., https://myschool.edu/myad.html works and the certificate signing authority is official) then the ad won't display to potential participants at all!
This is crazy!
What's worse is that many universities are not able to provide individuals with a signed SSL certificate. If that is the case, you can't really use the external HIT mechanism without getting an account on some web hosting site.
However, the psiturk Secure Ad Server solves this problem for all researchers.
Rather than getting your own signed certificate (a technically challenging process), when you use psiTurk, you can host your ad with us via https://ad.psiturk.org via a custom and unique URL made especially for you. We have already gone through the steps of getting an official, signed SSL certificate so you don't have to! psiTurk posts your custom ad text with us, and then participants access your task by first interacting with our secure server. We show them the ad, then forward them to you. No hassle, more potential participants!
A full "visual explanation" of the Secure Ad Server is provided here. Basically, you post the HTML of you "ad" to the psiturk.org cloud. Workers view the ad on the cloud server and decide if they want to accpet. If so they are forwarded to your local server or computer to complete the task.
Why use the psiturk.org Secure Ad Server?
As should be obvious, psiTurk already gets around a major technical hurdle for many scientists. However, the psiTurk Secure Ad Server not only serves up your SSL-signed Ad, but also provides you with some valuable data about people who view your HIT, people who accept it, and what other task they have completed on the psiTurk meta-platform. This can be very useful data. For example, when you use the psiTurk Ad server you can find out if your participants have done a version of your experiment before!
The public API for this data is coming soon, but just know that when you host your Amazon Mechanical Turk ads with us you are helping to build a valuable resource about which participants have done which types of experiments. This can be used to help filter your data or prevent certain participants from doing experiments for which they have already possibly been exposed to the important manipulation.
Sound great, how do I use it?
When you create a HIT from the command line in psiTurk your ad is posted to our servers. We begin forwarding people to your website instantly. You ad is never deleted (unless you want to delete it). Soon, you will be able to access statistics about who view, accepted, and returned your HIT and what other tasks they have completed on psiTurk. We also have plans to enable alternative ways of posting Ads to psiTurk including through a simple web interface. This would then allow researchers using survey-type (via Google Forms or Qualtrics) to take advantage of the features of the Secure Ad Server as well.