Being a mathematics website, the questions asked here are on pretty diverse areas. However, the weekly newsletter is the same for everyone.
I believe that being able to receive customized newsletters, i.e., receiving the most popular Q/A of the web in one's favorite categories/tags would be fairly interesting.
What is more, since the website has a high question/day rate, we wouldn't face too many 'empty newsletters' problems.
What do you think ? Is this doable ?