Its no secret that part of putting up any website or service is the consideration of security measures to stop people from abusing the system. And as you can imagine, those particular issues are probably doubled or tripled with a site like Mailinator (and of course Talkinator). Needless to say, I've gotten pretty good at unorthodox security.
Anonymity does indeed breed bravery.
The normal Mailinator use case is that you have a need for a quick email address to sign-up for some web service. Some people however, use Mailinator as an actual primary email repository. With the RSS feed, it acts as a convenient dropbox for newsletters or other semi-private email needs.
Unfortunately, there are some wacky funsters out there that think it might be fun to sign-up for some website over and over and over and over (and over). Often this is for some site that has "vote for your favorite band" or "sign up for a free gift" or some such thing.
The primary flaws of these systems is not Mailinator - its that these websites equate the idea of identity with email addresses. Seriously, long before Mailinator existed I had 3 or 4 email accounts that I actively used and another 10 I had probably abandoned. I'm not sure what those site designers were thinking - Mailinator or not, email addresses are FREE.
If you give someone something that has any value at all in exchange for free email addresses, they're going to ask for lots. I'm probably in a unique position to view this, but I see this idea as incredibly broken.
One option I had was to simply ignore this idea. Let crafty script-writers create systems that sign up for Wink accounts 1000 times an hour. (As I write this, I'm watching some automated system using several hundred IPs trying to sign-up for wink.com using Mailinator - and watching the Mailinator system dutifully send each request to the abuse page).
The problem with this is that someday, wink.com will catch on. And they'll ban Mailinator. This is sadly, a wonderfully broken solution to a still existing broken site design.
The problem for me is that I likely have legitimate users that want to sign up for Wink - and I want them able to do so (and I imagine Wink might want more users too, so by extension they'll lose some or all of the ones I lost). What's insanely broken for sites banning Mailinator is that there are tens of Mailinator-copy-cat disposable web services out there. Or even worse, someone with access to a server and a domain, who can install sendmail and create a few thousand accounts. Simply put, banning mailinator is like catching a single mouse and thinking you've solved the mouse problem.
You stop the bad guys, but for about a day until they implement a new system.
I had an interesting discussion with an acquaintance recently. During the conversation I described Mailinator to him. His mouth gaped open and told me he would look into it and probably ban it from his site. I asked what he would be banning it "from". He said he had a trial piece of software that people could sign-up for and download. And he wanted their real information to email them later (i.e. I did my best not to say that he was sending "spam") to see if they wanted to buy.
I noted that sometimes when I download software to try, I do want to enter my real email. I'm interested enough to want to be registered. But other times, I'm just in browsing mode. If given the chance I'd download and check it out, but if you give me too much impedance I'll probably just go check out his competitor.
In those cases when I'm just browsing, I'll use mailinator.
In other words, there are 3 types of potential customers. Those that don't care about his software. Those who really love the idea of trying his software and will do anything to do so. And those who are on the fence.
For obvious reasons, Mailinator is my "on-the-fence" tool of choice. If he banned it, he'd be refusing some subset of those potential customers. So it basically comes down to the question - whats better?
1) Definitely get user information you can spam later - or
2) get your product in front of as many eyeballs as possible.
Also noting the fact that NO email insures any relation to an actual person whatsoever (including yahoo, gmail, hotmail, etc.) - whats the point?
We continued our discussion and agreed that from a marketing perspective, you actually don't want to remove the email sign-up altogether. It actually brings value to some customers. If you remove it or make it optional, most everyone will skip it just to get to the goodies. But by leaving it and knowing that some people, using Mailinator or Yahoo or whatever, will give you temporary email addresses, you're maximizing your potential customer base.
It didn't hurt my argument to mention a few other disposable email services that he'd have to ban too. I sure don't know them all - they seem to come and go a lot. And that surely doesn't count ones that run semi-privately. Basically, it would be a fulltime job to keep up.
Oh. So, back to our script kiddies above. Mailinator includes a system to stop scripts from signing up for websites over and over. I love fun algorithms/data-structures so your homework can be to design something like Mailinator's abuse trigger system - a key-value datastruct that ages with time and is refreshed by lookups that come in at some notable (and tweaked) rate (in the same ballpark as a LRU cache, but definitely more dynamic).
Its unlikely a human will set-off the triggers but its possible. The sad part (for script writers) is that the algorithm doesn't trigger until their script gets going, so its probably a bit heart-breaking to spend a few hours perfecting a script to scrape Mailinator and then have Mailinator detect it only once it gets going and shut it down hard.
The first level is the Abuse Page. If you push it, Mailinator will ban IP addresses - but only under certain conditions. That's rather an imprecise way of stopping abuse. In addition, it looks for patterns of mailbox usage regardless of IP. An obvious one is that if one subject "Welcome to Wink!" shows up a lot in the read emails. Sadly, its difficult to distinguish valid users trying to sign-up for wink amongst the botnet hitting right now - so they'll probably get the abuse page too for the time being.
Potential site abusers taught me a lot and hardened the site considerably. Abuse attempts are still a common occurrence but far less normal than a few years ago. I assume many scripters went to less caring disposable services.
I often get asked if I care if sites ban Mailinator. I don't really. In some cases its prudent if you really do need to email people that use your service. In most cases however, its simply a knee-jerk reaction attempting to patch an otherwise flawed system. Not only is it a sure way to eliminate some potential customers, the flaw will show up again soon when the abusers shift to another method - and probably another method without Mailinator's facilities to stop scripts.
In the end, there is no real identity on the Internet. At least none past an IP address and a subpoena. At best, email is optional identity. And prudently, it should probably be treated that way.