There have been several case studies published showing that adding a “pop-over lightbox” (see an example here) can significantly increase opt-ins. Aweber, one of the e-mail services I personally use, has cited increases from 100%  to 200%!

I’m testing it on 2 of my sites right now;

What do you think, will I see an increase in opt-in’s?

I’ll let you know next week. 🙂