The blacklist is a list of sites that were noticed in a negative context like:
As a consequence they will be banned by search engines.
If someone thinks that his website was blacklisted by mistake, he can submit a reconsideration request.
Backlinks from blacklisted websites represent the so called bad neighbourhood and damage the linked website’s reputation.
When using the webmaster tools of a search engine (e.g. Google), the search engine will inform you about backlinks from blacklisted websites.
If you notice backlinks coming from websites with a bad reputation, you should contact the webmaster of that website and ask him to remove the link to your site. If the he refuses to remove the backlink, you can use the Google Webmaster Tools to disavow that link1).