You can also pre-insert name and emails into the opt-in forms using the url tags like so:
Check this CaptiFire example :
The opt-in form on the page will be pre-filled with the values from the parameters "wl_email" and "wl_name".
Here is an example from an EngagiFire Popup that is loaded after 3 seconds :
So this means you can use links from your emails and use your autoresponders email tags in the links - depending which provider you use they may look something like [[email]], it varies from an autoresponder to another.