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开发者_StackOverflow 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.

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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.

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You could have the emails sent to GMail through their SMTP servers and run some sort of crontab to pull down the emails from GMail, and process them from there.

They do allow you to have emails sent to your domain.com, see this page:

http://www.google.com/apps/intl/en/group/index.html