No, Word List Ninja does not place any claim on your intellectual property. The only legal right you give to Word List Ninja, through using the service, is the right to display the Suggestion Engine response to you, on your screen, on your logged-in device. Employees of Word List Ninja cannot see your submitted text nor the Suggestion Engine response.
Additionally, at this time Word List Ninja does not save your submitted text in a file or database. Submitted text is processed in memory, displayed to you via the Suggestion Engine, and is then dropped from active memory.