Hello,
Thanks for choosing us.
Well, this can be achieved if you use a HubSpot form in your newsletter.
You can add email field with a hidden field in the form and render that form anywhere you want on your site or other places. Then for the form create a new for a field for newsletter_subscriber and add options to it and make the “yes” option to default. Then add this field to the form and make it hidden.
Then whenever any user will submit this form then a new contact will be created on HubSpot and his property will always be marked to yes.
Then for lists create a new list and use that property as a filter and set filter value to “yes”. Then it will filter all the subscribers.
Moreover, if you want you can connect with us on skype:: makewebbetter
Regards,
MakeWebBetter