Have you noticed that in Sharepoint 2013 there is no possibility to log in as a different user ?
The link has been removed or forgotten in the UI.
It has always been a nice feature to have for admins and developers to be able to log in as a different user…
If you miss it so much though the link is still available:
and it still works in Sharepoint 2013.
I guess this would be one of the features that people will ask to build.
Another workaround is to use “run as” when launching the browser which by all means is a safer way…
Happy Sharepointing !!