As a followup to [this question](https://stackoverflow.com/questions/2179417/how-should-email-address-opt-in-implemented), I'm wondering what's happening to my TempData.

Scenario 1:

* user logs in
* user provides email address
* user receives email with validation code
* user clicks on validation url
* user is validated
* success msg is displayed via TempData set in Validate action

Scenario 2:

* user logs in
* user provides email address
* user logs out/times out
* user receives email with validation code
* user clicks on validation url
* user is validated
* success msg is not displayed via TempData set in Validate action

Now, I don't see a reason for the user to be logged in to validate. In Scenario 1, I put a "Success" message in TempData, and return RedirectToAction("Index"). Index action has an AuthorizeAttribute - if they're not logged in, they're redirected to the login screen (seperate controller).

I would like the login screen to display my message, but TempData appears to get cleared in this scenario. Am I misunderstanding the TempData lifecycle? Does it only apply to requests within the same controller?