Youtube Downloader - Illegal?

Hello BlackHatWorld! I've recently made a youtube downloader in C# which downloads a video directly from youtube and converts it to multiple file formats and saves it locally. Would it be illegal (In the United Kingdom) to sell (or even to distribute freely) on the internet? Would I be able to be sued by YouTube (Google) or anything similar?

Thanks in advance!

The technical answer is "no".

However, Big G have been cracking down on these type of websites lately (especially the ones that simply rip audio) due to external marketing forces of the creative media industry (unfairly entitles, one might argue).

However, since yours is software it should not be any different than people running there own script in Java to convert the video. You could probably carefully label the software in the User Agreement stating that they agree not to use the software to violate any copyright and is only for personal use only etc.

Does your software convert other Flash video/HTML5 as well? The devil is in the details so you could probably avoid scrutiny whilst G set the targets elsewhere.

Make a disclaimer saying that by using the software the user agrees that they can only use it to download and convert THEIR OWN videos to different formats, and that you are not liable for misuse.

Thats an excellent idea, thanks. It only downloads & converts youtube videos right now (current formats are as follows: mp3, mp4, 3gp, flv, webM)