Importing content from a URL

I have a workflow in which the email delivery activity pulls the latest content from a URL at the time of execution. If I try to send email to 2000 users in a single execution, will ACS fetch the latest content from the URL 2000 times or pull the content only once during the preparation stage and use it to send emails to all 2000 users?. I have set the aggregate period as "No aggregation".

Thanks,

Rahul