I have played around with Lamson. It still requires app developers to install, customize and maintain. I'm trying to understand if there is a market for a service that makes it super-simple to process incoming email.
"It still requires app developers to install, customize and maintain" That's kind of the job of a developer, right? if he uses a "simple service" he's not developing but he's a "User" using a service and outsourcing the development to the service provider.
Personally, I'd pay for a service that let me point my MX records somewhere, then be able to specify if I wanted a webhook called, or to get the emails pushed to S3, or a message queue... or some combination thereof. I'd still be developing, just not worrying about the mail server interaction itself.
There are lots of "simple services" that make developers jobs easier. Why write my own file storage system when I can use Amazon or Cloud Files?