Q:

Processing all the email sent to a specific domain

Requirement:
I am writing a web application (Rails on Heroku) through which users can create groups and user should be able to post a message to the group simply by sending an email to the group.
This is what tumblr.com does: each blog is associated with an email address(randomly generated) and user can post to the blog simply by sending an email. Also posterous.com has this feature.
Question:
What is the best way to architect a solution like this one? Comments? Ideas?
I see 2 ways of doing this:
1) Hosting my own email server (sendmail or postfix) on Amazon EC2 and having some script to process all the incoming email? 
This will give me a lot of control but an email server to maintain.
2) Have the email server hosted somewhere and just have to write the email processing script would be nice however I do not know of any email cloud service to which you can tell: "please accept all the email for mydomain.com".
Thanks in advance for any help.

A:

I think I am going to go with http://cloudmailin.com. They even have a nice Heroku plug-in. It would be nice to hear any good or bad experience from somebody that tried this out.

