As these screenshots show, some incoming links on YouTube videos are found to contain username/passwords of FTP servers that could allow anyone to login into these servers.
If Google doesn't fix this immediately, it could possibly become a big security issue for FTP sites whose credentials are now available in Google cache.
Earlier these YouTube links had revealed clicks on Adsense Gadgets ads. The latest issue was discovered by Rohan Pinto of konkan.tv/.
To ensure that your FTP servers are not in the YouTube database, run the following query:
site:youtube.com "clicks from ftp" your_server_name