Landing page. Visitor accidentally enters invalid email address and clicks send. No validation = Gone. You lost them. You can't email them for a correction. W

Landing page. Visitor accidentally enters invalid email address and clicks send. No validation = Gone. You lost them. You can't email them for a correction. With validation = You catch the issue before the visitor leaves and you ask them to fix it. Sure, it doesn't verify the 1 to 1 relationship between the email and the person. That requires a round-trip verification. I get it. At least you ensure that it isn't all garbage-in to begin with. The other aspect of email verification is that you don't have to choose to bug the user with the results. Depending on what it is, if someone enters an obviously junky address you can simply tag that email as potential crud in your database. Someone would then manually look at these every so often for cleanup or re-categorization. I don't like the idea of looking signups or customers in a transaction where both parties are interested in transferring the information accurately. That's a use-case where validation works well. Now, regarding your last name. The issue is cause by programmers who simply go around grabbing code off the internet without vetting it in any way. There are email "validation" regex expressions out there that are horribly wrong, yet people post them on blogs and others use them without question. It's unfortunate.