I'd like to track who contributes to my Crowdsourced story map so I can communicate with them later. Can the "Code Attachment" setting shown here be used to add a FB tracking pixel to the map?
No, the code attachment will you to attach a zip file of code to the item that will allow you, or others to, download. If you look at the original template items (those in the gallery) in ArcGIS Online (AGO), they will provide you a download of the template that you can host on your own server.
The AGO platform does not allow you to upload or host code that can be run on the platform. This is a security restriction to prevent hackers from running unauthorized code that would attack our servers or our user's computers.
We do open source all our story maps so you can download and modify them as you need to. Once you customize them, you will be required to host the app on your own server. Once you have it hosted, you can reference your version of the app in AGO as item so you can have it in your content or added to the template galleries. Although, it is referenced in AGO, all the code will be running from your servers.
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