What is the best Email Address Manager out there? (think Groupon)

For instance, someone comes to your site and enters an email....you later send them an email letting them know of a great deal, like Groupon.

Any ideas? I heard of ExactTarget, is that any good?

 

Never heard of exact target before but the site and services look pretty good. Interesting.
Why can't you simply use an autoreponse like aweber or getresponse? I'm not sure if I
understand the difference between what you are thinking and those standard services.

 

You should try email responder

 

any other suggestions?

 

http://mailchimp.com/ ??

 

never heard about exact target and i think you should use mail responder.