For an example, if you click on the jQuery example query that you posted, one of the search results is "greenjquery.com". When you click on it, it says "@greenj

For an example, if you click on the jQuery example query that you posted, one of the search results is "greenjquery.com". When you click on it, it says "@greenjquery" is not available on Twitter, though it's available when you try to register on Twitter.