the best way is to define for each and every Notice where you want to have it displayed.
display Notice at the Homepage (Forum List) only:
- click the specific Notice in ACP
- go to the Tab named "Page Criteria"
- at the very bottom you see a field named "Content Template is:"
- activate this field and enter the wording "forum_list" into that field (without the quotes, just the text)
As per above example, your Notice will only show at the Homepage (Forum List), but will not show at the "Register Page".
By figuring out the template-name, e.g.: "forum_list", you can define at which page you want to display a specific Notice.