I helped run the infrastructure for a reasonably large site. Occasionally while debugging an issue I'd be looking through our outbound delay queue -- sure enough, there'd be at least a dozen typo variations of gmail, yahoo, hotmail sitting there waiting to time out. And these were for customers who'd made an actual purchase and entered their email address twice.
Definitively proving that 'please confirm your email address' fields are not nearly as effective as the designers thought it would be.
On an unrelated note, fuck those fields. That is all.
edit: OK that's not all. Anyone else who's sick of websites interfering with your copy/paste operations, find dom.event.clipboardevents.enabled in about:config and set it to false. HTH.
I don't think I've ever seen one that wasn't paste-disabled, though my knowledge is way out of date since I found out about the aforementioned config setting.
It was definitely a case of a PM coming up with a quick and cheap 'fix' to the problem of getting so many people typing their email address wrong the first time.
We (from the tech side) put together a bunch of options, including validating the domain and giving the user feedback if delivery doesn't succeed immediately.
But it was put on a backlog of 'nice things to implement' and never delivered.
I love old-style internet websites like this. It makes me happy they haven't sold it and share some of the numbers.