Currently only showing up within listings for mammoth sites like Amazon, Wikipedia and The New York Times, the second search box allows users to search within the given
site while still on the Google homepage. Questions remain about whether this feature will only come up for sites that already use Google tech for their own site search--and more importantly--how it
will influence user behavior and the search marketing practice.
One reader said that it just created "more real estate to fight past," while another said "It's a whole new ball game." Readers also noted that the secondary box showed up during searches for "NASA" and "National Geographic."