I've accepted an answer, but sadly, I believe we're stuck with our original worst case scenario: CAPTCHA everyone on purchase attempts of the crap. Short explanation: caching / web farms make it impossible to track hits, and any workaround (sending a non-cached web-beacon, writing to a unified table, etc.) slows the site down worse than the bots would. There is likely some pricey hardware from Cisco or the like that can help at a high level, but it's hard to justify the cost if CAPTCHA-ing everyone is an alternative. I'll attempt a more full explanation later, as well as cleaning this up for future searchers (though others are welcome to try, as it's community wiki).
情况
这是关于woot.com上的垃圾销售。我是Woot Workshop的总统，Woot Workshop是Woot的子公司，负责设计，撰写产品描述，播客，博客文章，并主持论坛。我使用CSS/HTML，对其他技术几乎不熟悉。我与开发人员密切合作，在这里讨论了所有的答案(以及我们的许多其他想法)。
可用性是我工作的重要组成部分，而让网站变得令人兴奋和有趣则是剩下的大部分工作。这就是下面三个目标的来源。验证码损害了可用性，机器人从我们的垃圾销售中偷走了乐趣和兴奋。
机器人一秒钟就会在我们的首页上猛击数十次屏幕抓取(和/或扫描我们的RSS)，以寻找随机垃圾销售。他们一看到这个，就会触发程序的第二阶段登录，点击“我要一个”，填好表格，然后买下这些垃圾。
评价
lc:在stackoverflow和其他使用此方法的站点上，他们几乎总是处理已验证(登录)的用户，因为正在尝试的任务需要这样。
在Woot上，匿名(未登录)用户可以查看我们的主页。换句话说，撞击机器人可以不经过身份验证(除了IP地址之外基本上无法跟踪)。
所以我们又回到了扫描IP, a)在这个云网络和垃圾邮件僵尸的时代是相当无用的，b)考虑到来自一个IP地址的业务数量，捕获了太多无辜的人(更不用说非静态IP isp的问题和试图跟踪它的潜在性能影响)。
还有，让别人给我们打电话是最糟糕的情况。我们能让他们给你打电话吗?
布拉德克:内德·巴切德的方法看起来很酷，但它们是专门设计来击败为网络站点构建的机器人的。我们的问题是机器人是专门用来破坏我们网站的。其中一些方法可能只在很短的时间内有效，直到脚本编写人员将他们的机器人进化为忽略蜜罐，从屏幕上抓取附近的标签名称而不是表单id，并使用支持javascript的浏览器控件。
lc再次说道:“当然，除非炒作是你们营销计划的一部分。”是的，绝对是。当物品出现时的惊喜，以及当你设法得到一件物品时的兴奋，可能比你实际得到的垃圾一样重要，甚至更重要。任何消除先到/先得的东西都不利于“赢”的快感。
novatrust:就我个人而言，欢迎我们新的机器人霸主。我们实际上提供RSSfeeds，允许第三方应用程序扫描我们的网站的产品信息，但不是在主站HTML之前。如果我的理解正确的话，你的解决方案通过完全牺牲目标1来帮助目标2(性能问题)，并放弃机器人将购买大部分垃圾的事实。我给你的回答投了赞成票，因为你最后一段的悲观情绪对我来说是准确的。这里似乎没有什么灵丹妙药。
其余的响应通常依赖于IP跟踪，这似乎是无用的(僵尸网络/僵尸/云网络)和有害的(捕获许多来自相同IP目的地的无辜的人)。
还有其他方法/想法吗?我的开发人员一直在说“让我们只做验证码”，但我希望有更少的侵入性方法，让所有真正想要我们的垃圾的人。
最初的问题
假设你卖的东西很便宜，但有很高的感知价值，而你的数量非常有限。没有人确切地知道你什么时候会卖这个东西。超过一百万人经常来看你卖什么。
你最终会发现脚本和机器人试图通过编程方式[a]找出你何时出售该道具，[b]确保他们是第一批购买该道具的人。这很糟糕，有两个原因:
你的网站被非人类攻击，拖慢了所有人的速度。
编剧最终“赢得”了产品，让常客感到被骗了。
一个看似显而易见的解决方案是为用户在下单前设置一些障碍，但这至少有三个问题:
The user experience sucks for humans, as they have to decipher CAPTCHA, pick out the cat, or solve a math problem.
If the perceived benefit is high enough, and the crowd large enough, some group will find their way around any tweak, leading to an arms race. (This is especially true the simpler the tweak is; hidden 'comments' form, re-arranging the form elements, mis-labeling them, hidden 'gotcha' text all will work once and then need to be changed to fight targeting this specific form.)
Even if the scripters can't 'solve' your tweak it doesn't prevent them from slamming your front page, and then sounding an alarm for the scripter to fill out the order, manually. Given they get the advantage from solving [a], they will likely still win [b] since they'll be the first humans reaching the order page. Additionally, 1. still happens, causing server errors and a decreased performance for everyone.
另一种解决方案是经常监视ip攻击，阻止它们进入防火墙，或以其他方式阻止它们排序。这个可以解2。和阻止[b]，但扫描ip对性能的影响是巨大的，可能会导致更多像1这样的问题。比编剧自己造成的还要严重。此外，云网络和垃圾邮件僵尸的可能性使得IP检查相当无用。
第三个想法，强迫订单表单加载一段时间(比如半秒)，可能会减慢快速订单的进度，但同样，脚本编写人员仍然是第一个进入的人，在任何速度下都不会对实际用户造成损害。
目标
将道具卖给非脚本人。
保持网站运行的速度不被机器人减慢。
不要让“正常”用户完成任何任务来证明他们是人类。
以下是我的看法。攻击机器人所有者的投资回报率，这样他们就会做你想让他们做的合法事情，而不是欺骗。让我们从他们的角度来看。他们的资产是什么?显然，无数的一次性机器、IP地址，甚至可能还有大量不熟练的人愿意做无聊的工作。他们想要什么?总是在其他合法的人得到它之前得到你提供的特别交易。
The good news is that they only have a limited window of time in which to win the race. And what I don't think they have is an unlimited number of smart people who are on call to reverse engineer your site at the moment you unleash a deal. So if you can make them jump through a specific hoop that is hard for them to figure out, but automatic for your legitimate customers (they won't even know it's there), you can delay their efforts just enough that they get beat by the massive number of real people who are just dying to get your hot deal.
The first step is to make your notion of authentication non-binary, by which I mean that, for any given user, you have a probability assigned to them that they are a real person or a bot. You can use a number of hints to build up this probability, many of which have been discussed already on this thread: suspicious rate activity, IP addresses, foreign country geolocation, cookies, etc. My favorite is to just pay attention to the exact version of windows they are using. More importantly, you can give your long-term customers a clear way to authenticate with strong hints: by engaging with the site, making purchases, contributing to forums, etc. It's not required that you do those things, but if you do then you'll have a slight advantage when it comes time to see special deals.
Whenever you are called upon to make an authentication decision, use this probability to make the computer you're talking to do more-or-less work before you will give them what they want. For example, perhaps some javascript on your site requires the client to perform a computationally expensive task in the background, and only when that task completes will you let them know about the special deal. For a regular customer, this can be pretty quick and painless, but for a scammer it means they need a lot more computers to maintain constant coverage (since each computer has to do more work). Then you can use your probability score from above to increase the amount of work they have to do.
To make sure this delay doesn't cause any fairness problems, I'd recommend making it be some kind of encryption task that includes the current time of day from the person's computer. Since the scammer doesn't know what time the deal will start, he can't just make something up, he has to use something close to the real time of day (you can ignore any requests that claim to come in before the deal started). Then you can use these times to adjust the first-come-first-served rule, without the real people ever having to know anything about it.
The last idea is to change the algorithm required to generate the work whenever you post a new deal (and at random other times). Every time you do that, normal humans will be unaffected, but bots will stop working. They'll have to get a human to get to work on the reverse-engineering, which hopefully will take longer than your deal window. Even better is if you never tell them if they submitted the right result, so that they don't get any kind of alert that they are doing things wrong. To defeat this solution, they will have to actually automate a real browser (or at least a real javascript interpreter) and then you are really jacking up the cost of scamming. Plus, with a real browser, you can do tricks like those suggested elsewhere in this thread like timing the keystrokes of each entry and looking for other suspicious behaviors.
So for anyone who you know you've seen before (a common IP, session, cookie, etc) you have a way to make each request a little more expensive. That means the scammers will want to always present you with your hardest case - a brand-new computer/browser/IP combo that you've never seen before. But by putting some extra work into being able to even know if they have the bot working right, you force them to waste a lot of these precious resources. Although they may really have an infinite number, generating them is not without cost, and again you are driving up the cost part of their ROI equation. Eventually, it'll be more profitable for them to just do what you want :)
希望这对你们有帮助，
Eric
