They allow players to spin the reels of a pokies game without using their own money.
http://www.prepody.ru/topic76517.html
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https://mmomakemoneyonline.net/threads/ ... us.458195/
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https://talk.hyipinvest.net/threads/196315/
http://forum.spolokmedikovke.sk/viewtop ... 7&t=966822
https://www.ww2.site/forum/viewtopic.php?t=56259
http://oldsite.giessen46ers.de/fantalk/ ... 3&t=172359
http://users.atw.hu/tunedthings/viewtop ... 384#335384
http://forum.bandingklub.cz/viewtopic.p ... &t=1311734