I would like to hide my subdomain name from the outside world. For eg. If I have a domain name abc.example.com then I donot want any search engine or outside world to know about the existance of abc.example.com as a subdomain. I know if I do not provide any links any where on a page then search engines won't pick it up. But is there any other measures I should take to prevent this from happening?? Also do the toolbars like google, yahoo or alexa automatically pick up which url i am visiting? Thank you for your inputs.
One thing you can do is deny spiders in your robots.txt file. This will only help with compliant robots. If I had something I did not want world to see would put in password protected directory.
Smyrl is correct either password protect the directory or put this in yoru robtos.txt User-agent: * Disallow: /abc/ this will ofcourse stop spiders not humans
Definitely, putting a password in .htaccess is the best way to protect that domain. Also, keep a check on your log files to see who is accessing this domain. Or you can restrict the visibility of that domain to certain ips provided you access it from some specific ips only.