That would be rather easy. Make a bookmarklet that redirects you to a site, which then presents you the page with an overlay. Cross-site scripting policies prevent a naive implementation.
I think it already has been tried. I don't think it's all that useful, but if you really want, send me an email (see my profile for address), and I will build it for you.
Ha, I love the idea, but I have no idea how it would be implemented. If you want to make it, go ahead. I'm sure a lot of people would be interested. I'll come back once I understand how the internet works.
I think it already has been tried. I don't think it's all that useful, but if you really want, send me an email (see my profile for address), and I will build it for you.