Looking for a way that will collect visitors emails before letting them view the blog posts

I am looking for a way that will collect visitors emails before letting them view the blog posts.

What I want to do is let visitors browse the blog posts, view all categories and browse article titles and summaries - but when they click on a particular blog post and want to view the whole post, I want to require them to enter their email before viewing - NOT a full blown registration with password.

I need to store these emails somehow so I can export them to MailChimp or a similar ESP.

Then I am thinking to store their info in a permanent cookie or something like that so they don't have to enter their email again if they are using the same browser.

What would be the best way to accomplish this?