PRE-EMPTIVE PATENTING
Pre-emptive patenting, defined as patent filings whose main effect is to hamper the grant of other
patents. Patent applications can be used defensively to prevent the grant of exclusive rights over markets and technologies, in order to ensure freedom to operate (FTO) or keep competitors out of a given technological field (MARKET EXCLUSION).
Defensive (BLOCKING) patents are primarily motivated by a desire to secure freedom to operate while at the same time, possibly serving to prevent entry by others into given markets or technologies.
Offensive patents aim at preventing others from using a technology. They can serve to leverage
opportunistic licensing deals or advantageous settlement conditions from litigation threats

Pure-X, that is, applications cited for compromising (partially or completely) the patentability of other applications.
Preventing others from patenting with patent filings that are later withdrawn can result in a patent-free area and possibly an effective means to ‘cut through the patent thicket’ in some fields.