Why? I need to send this message to you now so that I can legally contact you after GDPR comes into effect. After the transition to GDPR is complete organisations and individuals will have to ask you, explicitly, to opt in the first time they collect your information.
In the past it was acceptable to add people to mailing lists by default if they hadn't explicitly said they did not want to be contacted. In other words people could assume you opted in. This change is therefore very good for all of us as individuals.
This email constitutes me offering you a 'soft opt in' option. The 'soft opt in' option is a good compromise for entities with mailing lists to keep their list intact whilst complying with the new GDPR legislation.
Why the new list? It's not a requirement for me to create a new list for GDPR purposes. It's been a personal aim to improve the mailing list preferences before GDPR was announced. It is now a good opportunity to make those changes. The new list will have clearer groups for you to configure your contact preferences with.