Installed laminate floors typically "float" over the sub-floor on top of a foam/film underlayment, which provides moisture- and sound-reducing properties.
It is important to keep laminate clean, as dust, dirt, and sand particles may scratch the surface over time in high-traffic areas.
It is also important to keep laminate relatively dry, since sitting water/moisture can cause the planks to swell, warp, etc., though some brands are equipped with water-resistant coatings.
Quality glueless laminate floors use joining mechanisms which hold the planks together under constant tension which prevent dirt entering the joints and do not need "tapping" back together periodically.
Laminate flooring was invented in 1977 by the Swedish company Perstorp [en], and sold under the brand name Pergo.
Perstorp spun off its flooring division as the separate company named Pergo, now a subsidiary of Mohawk Industries.
The two companies have been in a great number of legal conflicts over the years, and today most, if not all glueless locking flooring is made under license from either Välinge, Unilin, or even a combination of both.