What to do with reader email?

I get around 100 email addresses a day from my readers. I know I should be using these for something but what and how? Any suggestions would be appreciated. Thanks!

It all depends of what your readers are interested for.

The first think you must take in consideration when starting an email campaign is to see why those persons give you those emails address.

So if I submit my email on a proxy website then you can send me proxy related products. If I submit my email to get an ebook send me ebooks...

Give us the niche and maybe we ca find the best answer together.