Recently I implemented a captcha system in Mailinator.
If you're a normal user - you've probably never seen it. That's because it doesn't get activated until emails with the same subject get read more than like 10 times in a minute. Needless to say, if you're using Mailinator to sign-up for something here and there, that's not a normal use case.
But if you're a script - or a person signing up for some website over and over and over (and over) - you hit this pretty fast. It has done a fantastic job of stopping scripts pretty succinctly and slowing down humans zealously working over some site. The main problem with the latter is that many of those sites don't like that and may then ban Mailinator. That's not good for anyone.
What surprised me about the captcha system is how many people emailed me that I broke their test scripts. That is, they had email system tests (i.e. "Thanks for registering!") that use Mailinator as an end point. Their test then (with variation per user of course) checks the Mailinator inbox that their system correctly sent the email.
ManyBrain, Inc. (the company that owns Mailinator) has offered for a long time testing packages that completely bypass Mailinator's abuse system for high-volume testing or other emailing.
I'd be interested in however in improving this service and making it more mainstream. If you use Mailinator for testing - or would like to - I'd like to hear from you.
How would you use it? What kind of volume? I can't believe anyone is excited about scraping HTML (that wasn't particularly designed to be scraped) to get test results. Mailinator already has a (secret, shhh) JSON interface thats not public. That would seem to be the way to go.
My thoughts is a JSON-based SOAP/REST/whatever API that allows testing scripts to read emails. Whats a reasonable method and threshold of use to start charging? Possibly a sister site to Mailinator itself would be a better home for the testing service.
If there's enough interest to support the development, I'd be excited to get this up and running.
Email me at email@example.com