Bitly does fetch the long URL of a Bitlink to retrieve page title and related information. Our requests respect the robots.txt standard (http://www.robotstxt.org).
If you wish to request our systems stop making these requests, you may do so by updating your robots.txt file on the appropriate domain. Note that we do cache a site's robots.txt for 24 hours, so it will take a day before the change takes effect.
The robots.txt stanza to disable this behaviour is: