Why outbound link integrity is important?
While inbound links from other sites increase your Google Page rank and your search engine positioning, outbound links does the opposite: weakens your PR. This doesn’t mean that you shall NOT link to others, but surely means that you have to carefully choose to which sites or pages you do it. And even if outbound links won’t make or break a site in general it can weigh in in the big rankings picture. So there is really no sense to link to inexsitent or faulty external resources. Checking your outbound link integrity will prevent you to loose ranking power.