You may have rules on signs at your server's spawn, or another way of communicating your server's rules. However, this plugin offers a superior solution. This requires users to agree before they can play, and looks much more professional and well thought out. You have records of who agreed to the rules and when, It is easy to update them, and people can view them anywhere.
How it works
When a user connects and they haven't agreed to your server's rules, they are put in game mode adventure. They see a title that says Rules, Agree to Play. The rules are sent to them in chat. Operators will see a message with the player's username telling them that they agree to the rules. Once they have reviewed them, they can click type /agree to start playing. They will be put in your server's default game mode. During this time, they are hidden from other players.
Commands
/rules - Lists the rules of the server
/rules add - Adds a rule to the server
/rules remove (rule #) - Removes a rule from the server, the one argument is the number you see when you run /rules
/rules reset - Forces all players to reagree to the rules next time they connect
/rules clear - Empties the list of rules for the server
/agree - Run to agree to the rules
Permissions
cucumbers_cr.rules.admin - Allows you to edit rules, reset agreements, and see updates for who has connected.