It should be "People violating this rule will be deducted n points."
c.f. People who win will be given/awarded prizes.
NOT e.g. 2. "Violating posts will be deducted 10 points."
You are not punishing "violating posts" this guy!
e.g. 2. Issuing meaningless topics and replies are prohibited.
("Issuing A, B, C and D" should be followed by "is".)
e.g. 11. "Advertising or propagating other forums without permission are prohibited"
("A, B, C OR D" is considered singular, and should be followed by "is".)
e.g. 8.
It should be "fewer than 4 words" where words are countable.
e.g. 9.
Once _______ found ... (the subject is missing.)
It's better to say "Once topics are found similar, the newly posted one will be closed."
e.g. 10
It should be "expressions".
e.g. 12. Everyone cannot open more than 3 topics per day.
It should be "No one can ...".
c.f. We never say "All of us cannot ...". We say "None of us can ...".
13. is chinglish.
18. It should be "over 50 replies" and "50 views".