For what it's worth - and I'm not saying it's not a good idea to provide conspicuous notice - there is absolutely no legal difference between doing this and not doing this.

See https://www.newmediarights.org/business_models/artist/do_i_need_put_copyright_notice_my_work

It probably makes it easier to find the wholesale site scrapers, and serves as some evidence of deliberate intent to infringe with the copy/pasters, but it is neither required nor does it add any weight to a claim under law.

Only registration of copyright will do that, but it gets a bit costly - probably only worth it for books or articles of great commercial value.