Is it a bad idea to use identical content across several domains?

Search engines generally group identical or near-identical pages together and choose one version to show. You won’t get several domains’ worth of search traffic; most of the others will simply be ignored. If the goal is to protect the phrase or brand, it’s usually better to choose one primary domain and 301-redirect the rest to it.

There isn’t necessarily an automatic duplicate-content penalty, but this can still look like a doorway-site network if multiple domains are created mainly to target the same searches. That kind of setup can lead to manual spam action, especially when the sites are thin and nearly identical. A single useful site with original pages is a much safer approach.

The setup can make sense when each domain genuinely serves a different country, language, or audience, but then the content should be meaningfully localized rather than copied word for word. Otherwise, owning the domains defensively and pointing them to one well-built site is probably the most practical option.

Canonical tags can help indicate which URL should be treated as the preferred version, but they don’t make several cloned sites valuable. If all the content is the same, consolidate everything on one domain. The extra domains can redirect there instead of splitting your authority and confusing visitors.