The portal uses the AJAX Feed API of Google, which requires a Google API key to work. A single Google API key is valid for a single domain (such as, foo.com) as well as the subdomains (such as, bar.foo.com).
Go to the Google sign-up page for the Google AJAX Feed API.
Click the Sign-up for a Google AJAX API key link.
The sign up page is displayed.
Follow the instructions provided.
Click Generate API Key.