Whenever you broadcast using your webcam either on a website or through programs such as Skype, Yahoo/etc the possibility of being recorded exists. In order to protect yourself you should make sure that you always watermark your broadcast. Using Many-cam or another software that allows watermarking will help protect your broadcast as most websites will not permit a watermarked image/video to be uploaded.
If you find that you were recorded there are a few things you can do.
1. If your videos/images are uploaded to a download site (4shared, Megaupload, etc) your best bet is to contact them first, give them the links to your downloads and request their removal. Upload sites are more apt to respond quickly as this violates their policy.
2. Contact the website that is posting your videos/images by using their Copyright violation/DMCA link; this will typically be located at the bottom of the page. If you cannot find one, use their “Abuse” or “Contact” link.
3. Go to netsol.com and do a ‘whois’ on the website posting your videos/images. In some cases you may be able to find the company that host the website and contact them as they may be in violation of the companies terms of service.
While doing the above may not always be successful, they are the steps you need to take to get your videos/images removed from a website.