Boxes became quite popular when DTP programs came on the market, just because all of a sudden it was easily doable, the same with different colored backgrounds

Boxes became quite popular when DTP programs came on the market, just because all of a sudden it was easily doable, the same with different colored backgrounds (even if it was just shades of gray). Generally not a good idea for a simple, b/w, serious layout. If I remember correctly, even horizontal rules weren't that common back in the days. German/Swiss typography called them "English lines", so I assume they were more common in the UK.