Disallowing email addresses because of "invalid characters".

Bad for you because:

• some of your users will abandon the signup process or not get on your mailing list
• it implies that your software stumbles over certain characters in text strings, and that you're not sanitising your inputs
• it looks like you don't know what you're doing

Bad for your users because:

• they'll have to remember to use a different email address to the one they happily use elsewhere
• they might have to sign up for that different email address from scratch

Since an email address is often the very first thing you ask of a visitor who wants to sign up, you're giving a bad first impression.

Not giving people an "unsubscribe" link

This includes giving people a link but going out of your way to make it inaccessible. Many emails, full of big garish CTAs, place the link they don't want you to press in a tiny font with a barely-contrasting colour in the middle of a dense footer?

Bad for you because:

• you'll end up getting reported for spam
• your users will end up blocking you

Not having a working and clear unsubscribe link

When you follow the link, does it tell you that you have unsubscribed, and is it clear whether it means unsubscribed from all mailing lists or just one? Is it clear which email address was processed?

Bad for your users because:

• they won't be confident that they have really unsubscribed
• they won't be confident that you have no other mailing lists with their name on

Not giving people an easy way of managing their email preferences in your app or on your site

This includes not giving people the option of removing the email address completely or deleting your account.

Bad for your users because:

• they won't trust you anymore

Using a "donotreply@" username

Yes, even if you give the user a different way to reply. If you don't have the staff to handle an email support desk, it's not difficult to automate email processing, even for a single user hosting a small domain.

Bad for you because:

• you'll miss out on feedback from people who can't find another way of contacting you
• you'll waste time asking people for the context of their questions - someone will send you a message on Twitter asking how to find out their order status, you'll tell them to use the contact form on your site, they won't include the right order reference number, you'll follow up asking for it... seasons will pass...

Bad for your users because:

• their interactions with your product feel impersonal
• they have to take multiple steps to get answers to their questions

Nagging people to sign up to a newsletter

This means popups, popunders, interstitial reminders, fixed position banners... remember, if you hate them, your users hate them. And you hate them. Obvious stuff.

Automatically opting people in

This is the worst sin, and I see it on

• forms which have an opt-in checkbox which is pre-ticked - users are less likely to untick an option than to tick one
• forms where every other check box in a group is opt-in but the label for this one is 50 words long - if your visitor is in a hurry, they will assume it behaves the same as the others
• forms where the opt-in or -out boxes are mixed together meaning some have to be checked and some left blank
• forms where the box to check to say you want to opt out resets to the opt-in state when any error on the rest of the form prevents you from submitting
• forms where you do not have the option of opting out, but they say you definitely can unsubscribe later if you ask nicely by some unspecified contact method

Bad for you because:

• you may well be violating the law
• your statistics on how many people signed up will be misleading, which in turn means you are probably misleading your stakeholders

Bad for your users because:

• they won't trust you with anything else...

...and you want people to trust you, right?

Cover image by Web Hosting on Unsplash