The module located in Server interaction -> Webservice search allows to communicate with other servers.
It can be used to fetch data but also to send values.
In this view, the Webservice search module is configured to make a query to the Flickr API and get a list of images based on the text entered in the search box. It will only return images that are located in the visible area of the map.
A new search is done when one clicks on the "Search on Flickr" button.
Then you can click on a result to see the corresponding image and its geolocation on the map.