I came across an article on negative margins this week and immediately realised how much potential they have which not many people use for.

This is especially true for cases when you have to position an element different from its natural order in the HTML code (for e.g. if you have to show using css a div element before a p element but in the HTML code the div appears after a p). You come across such instances when you do SEO for your websites and require the most appropriate html content to show first for the search engines but not so for the browsers.

The immediate solution I used to think of was using absolute positioning. But using negative margins is even simpler. Community MX has a very detailed free article on negative margins while A List Apart has the solution to the problem I mentioned above - using negative margins.

P.S. Using negative margins is not a hack.