said 9 months ago:
It’s a new Bing Webmaster Tool that allows you to submit URLs of spammy or low-quality sites that link to your website. You can submit URLs by page, folder or the entire domain. It sends a signal to Bing that you don’t want to associate your content with those links.
It’s interesting that Bing released the tool first because they have gone on record to say that those types of links don’t harm your site with Bing. They don’t help either.
With Google, however, they do hurt your rank especially since the Penguin update. I think more people were hoping it would be Google releasing the tool but I have heard it’s in the works.