HttpDelete action method selector attribute is used whenever we want to restrict action method to be accessible only via HTTP DELETE verb. Similar to HttpPost & HttpGet, HttpDelete also inherited from ActionMethodSelectorAttribute.
Attribute Usage: Only method
public ActionResult About()
Once we marked action method with HttpDelete attribute, it will throw an HTTP 404 not found error if we try to access it with other HTTP verb.
Check out ASP.NET MVC: Action filter series post to read about other available action filters.