The reaction score is built in to the forum software and it goes up the more your posts are like or reacted to. Trophy points go up the more you post, visit the forum, etc. and can be used for promoting members to different user groups that may have access to things that lower user groups don't have. The highest group is Cartaholic V.I.P. for members who donate to the forum to help with expenses for the server, forum software upgrade costs, etc.