How did this website get a custom search bar listed under their search results?

Question

Observe the following results for searching the text "dictionary" on Google:

Notice that there is a custom search box at the bottom of the listing for dictionary.reference.com. Is there any documentation floating around that explains the criterion by which Google decides to display such a search box?

Answer 1

To follow up from the answer above, here's the official Google blog post about the feature:

http://googleblog.blogspot.com/2008/03/search-within-site-tale-of.html

The key bit says: "This feature will now occur when we detect a high probability that a user wants more refined search results within a specific site. Like the rest of our snippets, the sites that display the site search box are chosen algorithmically based on metrics that measure how useful the search box is to users."

Answer 2

There is no criteria specified by Google and this isn't something a website controls. Basically Google uses an unknown criteria for deciding what sites it offers this for. But it's not hard to see that it only is applied to very large sites with a search feature that is commonly used. Wikipedia is another example of where you should see a search bar.

Answer 3

This isn't something that you can make Google do. Google only shows site links and a search box when:

• The query is for the brand name or site name (the user showed navigational intent)
• There is a single site that most of the users will click on.

We have another question What are the most important things I need to do to encourage Google Sitelinks? The answer for the search box is going to be very similar:

• Create a strong brand such that users really mean your site when they search for your brand name.
• Have enough inbound links and site reputation
• Make your site well crawlable with normal HTML links rather than JavaScript.

To also get the search box, you would need to have a large number of pages on your site. Enough that Google feels that a few links are not going to sufficiently satisfy user demand to dig deep into the site.