They reward loyalty with a range of bonuses and special rewards, including free spins on registration.
https://catrachosporelmundo.com/index.php?topic=25471.msg25980#msg25980
https://www.ww2.site/forum/viewtopic.php?t=252078
http://forum.animogen.com/viewtopic.php?f=9&t=1584698
http://tv-online.simple-otr-mirror-alternative.de/phpBB3/viewtopic.php?f=39&t=6565
http://biopharmamash.com/viewtopic.php?t=1928490
https://phantom.everburninglight.org/archbbs/viewtopic.php?pid=748976#p748976
https://muchroom.ng/index.php?topic=19310.new#new
https://www.ww2.site/forum/viewtopic.php?t=327086
https://muchroom.ng/index.php?topic=89624.new#new
http://www.lada-xray.net/showthread.php?p=269228#post269228
https://talkingpoints.org/subx/showthread.php?tid=41385