PHP: URL Howto: This is a little known but great feature of the PHP Web site.
If you write in a PHP.net URL, like http://www.php.net/links, first this URL is matched against the PHP.net pages. If there is a page named links.php, then you’ll get that page immediately. This type of shortcut makes easy to type in a link in an IRC conversation or mailing list message. If the script finds no page with this name, it tries to find a manual page.
Basically, they integrate the search string with the URL. Since PHP is a short URL, it’s easier just to rip off the url and search term together than click a bookmark and enter the search term in the box.
Amazon’s a9 does this too. With just a short URL, it makes it really simple to get to and link to stuff, like this.
This handy little site joins sites like php.net and A9 in offering "functionality by URL." Enter "whois.sc/" and any domain name in your address bar, and you get the whois data — like this. Eliminates a step from the normal pattern: enter the domain, wait for the page…