Patent flooding can be used to gain several patents on minor variations of the originally registered patent from a competitor. This is done to limit the possibilities for the competitor to improve or develop variants for its registered patent. This can then force the competitor to get cross licensing from the rivalling party who started the patent flooding. By means of patent flooding a company can thus prevent a competitor from fully exploiting its patents. It is essential to conduct a full patent search also for variations of a patent before one registers a patent. It is especially true of foreign patent applications.

The USA and Japan are the two leading countries when it comes to patent filing and also patent flooding. It has become known as the registration of patents for defensive reasons rather than for the purpose of using the patents for commercial gain. It is especially the large corporate entity that is guilty of this practice. By means of patent flooding corporations register hundreds of patent variations simply to prevent market domination by a competitor. With this trend also comes an increasing trend of cross licensing. The competitor can simply not fully exploit the potential of its patents without having to in some form or another get cross licensing agreements with the competitors.

The opposite of a defensive patent is the offensive or pioneer type patent. With the offensive patent an inventor carves a niche and gets the opportunity to exploit its patent fully. With patent flooding, however, the few rather valuable patents registered are overwhelmed by the hundreds of registrations for variants. In addition patent flooding also creates a backlog of examinations at the patent offices and thus prevents the system from operating as it should.