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Google's Sitelinks Search box launched in September of last year and webmasters are still scratching their heads asking how can my site show the search box in the Google search results?
As we discussed before, adding Sitelinks schema doesn't guarantee or even help you get this search box in the Google search results for your brand.
First, you need to show the search box in the SERPs and the schema itself only lets you control where the search results go, i.e. back to Google's results or within your own internal site search feature.
Google's John Mueller made it crystal clear yesterday that algorithms determine when and who gets the Sitelinks Search box in the search results and that markup makes no difference.
John wrote in a Google Webmaster Help thread:
As with sitelinks, Google's algorithms determine when this sitelinks search box is shown. Once we have your markup, we'll try to use it for the times where we do show it.
Forum discussion at Google Webmaster Help.
