How does a website know the Google query I used to find it?

search-engine

Solution

It is parsing your query from the query parameters in the `HTTP_REFERER` server variable, which contains the URL you're coming from and is provided in your HTTP request.

Problem

When I search for something such as "`rearrange table columns in asp.net`" on Google, and click the link to Wrox's forum site, the site greets me with a message such as "Your Google search for 'rearrange table columns in asp.net' brought you to Wrox Forum...". How does a site know what query I typed into Google? And how could I add such an ablity to my site?

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