Obviously Google doesn't want you to download its content on your computer, however if you are downloading for personal use, it is not illegal to download a YouTube video.
YoutubeDownload service respects owners' rights and discourages users to use videos for anything that is against the copyright protection terms and conditions. Copyright infringement is in no way allowed on YoutubeDownload, and all the copyrighted contents are blocked from being displayed in the search results.
It is absolutely safe to download with YoutubeDownload. We are not responsible for the downloaded content itself, because we don't own it or developed it, but we guarantee the safety of our online downloading service.
Most of the time online YouTube downloaders that claim to be free make money by pushing ads on their users. This can be quite annoying. YoutubeDownload is not like that - it is free of charge and free of any advertising.