So, it sounds like the real issue is the timing of the clicks, then? We need a better way to determine clicks that happen within the first seconds of the email being delivered (could be bots) versus anytime after that (could be humans).
Yes and no. The timestamp of an individual click isn't going to give the context you want. It's (at best) about the the timing of a batch of clicks. If clicks were queued up for a short period of time, rather than being sent to the tracking server immediately, then the rate/breadth of a batch could be analyzed. The whole batch would be thrown out if it seems machine-made, or the whole batch forwarded to Marketo otherwise.
Yet this, too, isn't foolproof, since sometimes a mail scanner will only click one of your links, if it's still within the cache lifetime of the other links (they do cache results for a short period of time).
There's a foolproof way (using external tech, but simple) to tell whether a human clicked on an email if you can get them to engage further. That is, if someone fills out a form on the CTA target page, or even just goes to another page on your site, then you can see a trustworthy Clicked Email activity for the specific link in a specific email. But if they merely view the immediate target page and don't do anything else, it's still nearly impossible.
Right, that makes sense.
I've thought about it more, and I do think that setting up a dummy link in emails the way I described is helpful, but mostly in determining the variance of how many clicks could be due to bots - not necessarily in providing exact numbers.
For example, we sent an email recently that included the dummy link. I created a smart list that included all people that only clicked on the dummy link, and the number was about ~900. Then I created a smart list that included clicks on any other link besides the dummy link, and the number dropped to ~200. This means that even if a percentage of those 900 people who have bots scanning their emails do actually convert to real clicks when that person opens the email and clicks, it's still a helpful data point for us to see what the spread is.
It may not be an exact science, but it has helped our team re-consider our baseline and targets for email engagement.
Thanks again for the thoughtful responses and feedback.
I think you're misinterpreting what's probably happening with your dummy link. The link is itself arousing suspicion -- never a good thing for deliverability -- because it appears to be hidden (note that no link is ever actually hidden -- in my mail client, for example, I'm sure your CSS or whatever you're using to hide will have no effect and I'll see it plain as day). As a result it's scanned more often than the others, which can make more use of cached results. That's inflating the level of scrutiny by mail scanners, so you're moving the goalposts (if you will) just by including the link.
Since slightly after the dawn of spam, we spamfighters (I'm also a mailserver admin from way back) have looked as much for attempts to obfuscate malicious content as we have for the content itself. That is, it can be easier for anti-abuse systems to detect that you're trying to hide something than it is to figure out what makes it worth hiding. So really, the whole idea of a "hidden" link is counter to the goal of successful email marketing.
That's actually fantastic feedback, and it makes a lot of sense. I wonder if simply removing the "hidden" css would make it any different. I definitely hear your point about tracking web activity, and whether a desired action was taken to gauge campaign success over clicks, and I agree that's the best way to go. It's just tough to let go of clicks as a reliable metric!
Thanks for being so thorough with your explanations.