How to tell if a domain has been penalized by Baidu and Google

When dealing with the inclusion of websites in the First-Zhai website classification directory, it is first necessary to understand whether the website has already been indexed by Baidu or Google, or if it has been penalized (K). How do we carry out this series of verifications? Please refer to the following:

1. By using the `site:` and `link:` search commands, check the indexing status of the domain name. If the index count is 0 but there are many backlinks, then the domain may have been penalized.

2. Directly input the website address into the search engine for a query. If you find that among several results, the domain is fully included in all of them, yet the `site:` command shows no results, then it is highly possible that the domain has been penalized. (One exception could be that the search engine has indexed the site but has not yet immediately published it in the search results.)

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