If you are seeing a user agent string of "bitlybot" in your web server's access logs, that is indeed us. Otherwise, it's someone else crawling your links by crawling Bitlinks. We do have a bot we use to retrieve some information for each new Bitlink, but our bot respects the robots.txt standard (
http://www.robotstxt.org), so if you add the following stanza to your servers' robots.txt, you will see our bot no longer accesses your links. Note that we do cache a site's robots.txt for 24 hours, so it will take a day before the change takes effect. Otherwise, you could configure your web server to examine the request's user agent, and if it sees "bitlybot", you could have the server return a 403 or similar.