These options are set from the Conv/Msg tab of the Options Manager interface. These "conversation options" affect new threads that are created through the user interface with the "Start New Thread"/"Create New Conversation" links and buttons.

Capitalize first letter in user-created subject lines: If checked, when a user creates a new conversation through the user interface, the first letter in the subject of the new conversation will be capitalized.

Create pages in user interface with "Add a Message" box: If checked, when a user creates a new conversation through the user interface, the new page will have an "Add a Message" box enabled. This will allow others to post follow-up messages to the original message. This option is checked by default, and generally should not be changed.

Create pages in user interface with "Start New Thread" button: If checked, when a user creates a new conversation through the user interface, the new page will have a "Start New Thread" button (or the equivalent functionality) enabled on it. Essentially, this results in a more "threaded" appearance. However, it also allows the structure of your board to grow out of control very quickly.

Limit user-created subject lines to ___ characters: If checked, when a user creates a new conversation through the user interface, the length of the subject line will not be permitted to exceed the number of characters you specify in the box. This is to prevent abuse of the display by a user who sees fit to create a new conversation with a very long subject. To enforce the limits, you must both check the box and supply a valid limit in the box.