Laws regarding email marketing are designed to protect you and your subscriber. If you’re “promoting or advertising a commercial product or service through electronic communication,” then you should be familiar with the CAN-SPAM Act and any other legislation that applies in your country.

UK anti-spam law is mainly aimed at restricting the sending of unsolicited marketing emails (i.e. spam) to individual subscribers. There are rules for sending email to businesses, but I’m going to mainly address communicating with individuals here.

You are allowed to send direct marketing emails to individuals if they have “previously notify the sender” of their consent. That is, they have ‘opted in’ to being a subscriber and receiving emails from you. Opting in means the subscriber must have taken positive action. It doesn’t count if they don’t deselect an opt in box that is pre-ticked. The usually accepted positive actions are to tick an opt in box or provide their email address in a field on a webpage.

In UK law the opt-in is considered temporary, with the subscriber only giving their consent ‘for the time being’. You can however assume their consent is valid until there is good reason for you to believe otherwise.

Every marketing email you send must clearly identify you as the sender and must also give the person receiving the email the ability to opt out of (or ‘unsubscribe from’) further emails.

Once someone has purchased from you, you may add them to your email list. Emailing advertisements to customers is not considered unsolicited email, and in general nor is sending such emails to businesses rather than individuals. However the subject of your advertisements should be related to your business. For example, you should not be sending advertisements about cheap holidays if this type of business is not related to yours in any way.

If you are going to let a third party advertise in your emails you should obtain the consent of your subscribers first. If you don’t, your emails might be regarded as unsolicited direct marketing.

If you buy or rent an emailing list from a third party, ask the list provider if you have the right to use it for email marketing. You are allowed to use lists of individuals collected by a third party on your behalf, providing it was made clear to the subscriber that their details would be passed to businesses offering the type of products and/or services that you offer.

Sending your emails through a reputable autoresponder service should make it less likely that you will break the law. However you need to be aware of their terms of service as they would probably cancel your account if you break any of them, whether on purpose or as a result of ignorance.

You should also be aware of any email marketing rules set down by your ISP. They can quickly withdraw their service if they receive justified complaints regarding your email marketing.

If you hire another company to manage your email list, you will still be held responsible if the company breaks any of these rules. In the UK the Information Commissioner would start proceedings against you because you would be regarded as the ‘instigator’ of the offending communication.

The best course of action is to give all your subscribers the opportunity to opt in and clearly explain what they can expect after they have signed up. Provide good, useful content, respond to any complaints or unsubscibe requests and you should be fine.

More information about CAN–SPAM compliance can be found here:
https://www.ftc.gov/tips-advice/business-center/guidance/can-spam-act-compliance-guide-business

More information on UK email marketing can be found here:
https://www.gov.uk/marketing-advertising-law/direct-marketing
http://www.lawdonut.co.uk/law/sales-and-marketing/marketing-and-advertising/your-email-marketing-and-anti-spam-law