One of our products here at work is a web-authoring tool. We let
people layer objects all over their page, and then export their project
into HTML.
From day one we've known that what we show them in our editor will not
be exactly what they see in their browser. HTML is abstract, browsers
have a little leeway regarding how they interpret a page.
We get several complaints from users, though, who very snuggly position
their text within their text boxes.