Not really....
you can whitelist email adresses yourself.... and regarding confirmation emails you have a pending queue.... let's say you sign up for something you then go to your pending queue and whitelist that yourself.
The spam that lands in my inbox is almost 0 meanwhile. The next version of TMDA should have incorporated a user authentification where one is being required to visit a webpage and enter a pwd from an image...
Right at the moment a simple reply is enough but spammers could adapt that too easily!