OpenSearch is a collection of technologies that enhances the search functionality of both websites and search engines by using a standard format for publishing search results. It was developed by A9 (subsidiary of Amazon), and version 1.0 was released in March of 2005.
For most websites, the coolest piece of this technology is the ability to include your search functionality in the browser's built-in search box.
For anyone reading this article on the CrossTech Partners Blog using IE7 or Firefox 2.0+, you should see the search icon in the upper right corner of your browser lit up. Click the down arrow to reveal the list of choices and you will see our CrossTech Partners Blog listed in the search providers. If you select the CrossTech Partners Blog listing, you can type right into the box and it will send the query to our search engine handler. It will handle requests exactly the same way as the search box we have in the upper right.
Also, if you add our search provider to your list, you will be able to take advantage of our search box no matter what site you are on. This is most useful for search-engine based sites such as Wikipedia, but can be useful for any site that contains searchable information.
Let's take this one step further. Since we now have a standard format for search requests/results, we can build a site that aggregate search results from hundreds of individual website search engines. Take a look at A9.com and you will see an example of how they aggregate multiple search engines into a single page.
With this technology, developers can create sites that search multiple product inventories, article databases, or any other search-based information store.
As trend in the Web 2.0 shifts more and more towards open standards it will allow developers to easily aggregate sources of information, and create more value for their users.