Google site switch

A "site switch" is a method used in a Google search to limit the search to only a specific website.  It is sometimes referred to as a "command option" and would probably only be used to search a website of interest that does not have a built-in search feature.  To clarify, you would probably not use this approach to search familysearch.org, or people.mnhs.org, or werelate.org because each one of these three genealogy-related websites has its own search feature.  On the other hand, most blogs do not have their own built-in search feature.
In general, the search command is in three parts;
   you would start the command with the topic or surname that you are searching for,
      followed by a space and "site:",
         followed by the specific website that you have chosen to search.

To try out using the command, go to the Google website (URL line with https://www.google.com) and type the following three parts into the search box ("Quass site:blog.eogn.com" (without the quote marks, of course)) and press the enter key or click on the Google Search button.
Because Dick Eastman's popular genealogy blog does not have a search feature, this command option limits the search to just his blog website.

You can read more about this topic by doing a Google search for "site switch" or "command option" which might lead you to

http://www.abc15.com/dpp/money/consumer/data_doctor/the-google-%27site%3A%27-switch---how-to-use-google-to-search-websites-that-don%27t-have-a-search-option

or to

http://www.rankpanel.com/blog/google-search-parameters/.