united-kingdom contract-law
Automatic website signup without user consent
<p>I was wondering what the legality is in the following situation.</p>

<p>User signs up to site A.  Just above the submit button user is notified that signing up to site A will also sign user up to site B (which they may not ever use).  They have no choice.</p>

<p>Site A is a blog and site B is an e-commerce site, both 'owned' by the same person.</p>

<p>Is this, firstly, legal? If so, is it advised? Or should the user always have the option to choose whether they want to signup or not?</p>

<p>I don't know what it means to register to a blog or sign up to a website, but I assume you are going to be sending these people email. If so, the CAN-SPAM Act is implicated. Sending people unsolicited can be not only annoying but also illegal.</p>

<p>If this is question is about sending people emails, make sure you provide an opt-out link in the emails that you send and honor the requests quickly. Here is some information which might help: <a href="https://www.ftc.gov/tips-advice/business-center/guidance/can-spam-act-compliance-guide-business" rel="nofollow">CAN-SPAM Act: A Compliance Guide for Business</a>.</p>

<p>Also, if kids are targets of your site, COPPA is implicated if you are collecting information about the kids which I mention only because "registering" and "singing up" usually means providing information.</p>

<p>All that said, if this is as literal as it sounds, and people are just providing some information which will be used as a credential to access your pages, there is no law against extending the reach of the permission. </p>

<p>If the contact details will be used for email marketing from the e-commerce website  then yes, there would be a breach of the Privacy and Electronic Communications Regulations.</p>

<p>In a nutshell the regs state that you must have prior consent to send marketing emails to individuals. It is unlikely that you could equate wanting notification of blog entries with wanting associated marketing emails.</p>

<p>An opt-in is arguably your only reliable way of staying the right side of the regs.</p>

<p>As an aside: if someone is signing up to buy something from an e-commerce site it is acceptable to have an opt-out option for marketing emails (i.e. you do not have to rely on an explicit opt-in). This is often referred to as soft opt-in.</p>
