Some web applications have a need to use multiple subdomains and certain situation also require dynamically adding new ones. For example, consider a multi-tenant web app that gives each user his own subdomain for a personal content stream or dashboard.
Many users felt that the process for this was complicated, as the user would need to add each subdomain individually through the portal, PowerShell cmdlets, or (more realistically) direct API calls. In case SSL is needed, it adds yet another layer of complication as each subdomain would require an individual SSL binding.
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