Two things are essential to keep people coming back to any site:
1) Good content, and
2) Easy access to the content.
As silly as it seems, one or two extra "clicks" to find the content will prevent people from coming back. So ditch the "enter this site" index page. It serves no real purpose and puts an unnecessary "click" between your users and your content.
Also, your site is absolutely useless for people with visual disabilities; not just blind people, but anyone who needs a larger size font or more contrast between text and background. The *least* you could do is provide an email link or form in html so that people unable to use your site can contact you.
Usability, usability, usability!