No, you don't necessarily need to register a new user account for each reporter. With YouTrack, you can support your external customers or maintain a service desk for internal users with helpdesk projects featuring free unlimited reporters.
Customer requests can be collected via email or a customizable form and then integrated into a website or internal portal. These requests will then land in the helpdesk project as tickets.
Your reporters (customers) get updates on their requests via email or in a convenient overview of the tickets in YouTrack. Each response from the reporter is saved as a new comment in the ticket. If you create an FAQ and publish a knowledge base for your customers, reporters will be able to find answers with powerful search options and participate in the relevant discussions.
As a result, your support team can process all reporter inquiries in YouTrack. However, there is a cost associated with each account for your support agents.
More information about YouTrack Helpdesk pricing can be found here.