Question: I am trying to set the permissions on a folder so that a visitor to the website can upload a file via a file upload script, and I was not sure how to correctly set the file permssions to make this happen. Which user do I neeed to give write permission to?

Answer: This will depend on the scripting technology you're using for the upload, and on which server you're on: 

Plesk 7.0.3 (web6, web8): 

For PHP or ASP scripts: add MODIFY permissions to the the IUSR account.

For ASP.net scripts: it will run under ASPNET by default unless you have impersonation enabled in your web.config (which you should use if using asp.net), in which case it will impersonate the IUSR account - add MODIFY to the appropriate account.

Plesk 7.5.6 (web10, web12, web14, web16):

For PHP scripts: add MODIFY to your IUSR account

For ASP scripts: add MODIFY to your IWPD account

For ASP.net pages: it will run under your IWPD account by default unless you have impersonation enabled in your web.config (which you should use if using asp.net), in which case it will impersonate the IUSR account - add MODIFY to the appropriate account.