** there are quite some filters targeting particular users
** there are also some targetting particular pages (verify!), although this clashed with the guidelines
** and there are some filtering in general
** there are also filters such as 199 (Unflagged bots) which were implemented in order to track something which was not quite malicious or abusive and were thus deemed inappropriate use of filters by the community and consequently (quite swiftly) deleted
* How do filters emerge?
** an older filter is split?
** several older filters are merged?
** or functionality of an older filter is took and extended in a newer one (479->631)
** new condition(s) are tested and then merged into existing filter