title: Code to check whether site has been listed on search engines and directories
body: <p>I am currently developing an application in Rails, which requires to check whether a website has been listed in Google, Bing, Yahoo, Yelp and Yellow Pages. From my research the best is to check site: domain.com on Google and Bing and look for results and check in Yahoo directory for the domain.</p>
  
  <p>Is there any other way to do it? I mean some code snippet to check on domain's home page or using their API or something like that. Also how to check on Yelp and Yellow pages.</p>