sign-up model with returning subscribers

Hi,

I have an interesting question (I think) about the whole member/registration setup on my website:
My website should be accessible to everyone, free. They can see all pages and all content (videos) with Intros/Outros and with added advertisement.
If they want to watch the videos without the advertisement, they can simply enter their email address and become a member of my website, still for free! They will then get access to exactly the same website environment but the videos are without adds (member only content).
The reason of course is to get their email addresses. Later I will drop additional content they have to pay for…
I handle the subscriptions with mailchimp.
So how works this setup with s2member? Is it possible at all? What I would like to have is that people sign up and get member-access. And when they return, the only thing they have to do is again only enter their email addresses and they are in te members-only area of the website. A combination of sign-up and log-in so to say.
An example is this site: scottsbasslessons.com
Any ideas? I would really appreciate it!
Thanks! Kind regards,
Florian