swa66 - 12:14 pm on Apr 6, 2009 (gmt 0)
Most trouble I see that people have with floats is that they think a float is a column, more or less like how a cell in a able row reacts. The example you pointed to does make it seem that way on first looks. But you really should see a float as the generalized version of an image with horizontal alignment
<img src="1.jpg" alt="image" align="left" />.
With floats it's imported to know the parents will not stretch to encompass them anymore (unless they are floated themselves) as the floated element isn't part of the flow anymore. However floats do affect the flow and aside of shoving content to a side, they can also be "clear"-ed.
Combining that all with a trick to position backgrounds on parents when you want a background to go on beyond the height of a float usually does the trick.