When is the SEO inappropriate?

When is the SEO inappropriate?

When you don't want a page or domain to be found by a machine and crawled. Sometimes the less findable status of a page or domain is desirable for a short period of time. The security of the page or domain may not be critical, and yet, it's best if no one besides invited visitors sees it until it's revised. In the meantime. the invited visitors need something from it.

I suppose fake or phishing sites that impersonate authentic sites also don't want to be machine findable--instead, they're just reachable via email links or the like. Search engines could conceivably serve an authentication function of sorts in this case. The author and publisher tags that Google advocates seem to lead in this direction.