If you have some inbound links from sites of low quality it will damage your search engine rankings. Only good quality inbound links will improve you page rank as well as search engine rank. How do you justify high quality inbound links?
1. If you have a page with the content written about “music”, if your inbound links come from same kind of sites in which content is written about music only even with low page rank, that can be treated as good quality inbound link.
2. If your inbound links come from a page with high page rank, that also can be treated as high quality inbound link.
Low quality inbound links may give effect on your search engine ranking. If your page has the content about ‘health tips’ and your inbound link come from a page whose content is about cats and rats of aunt, that can be treated as low quality inbound link which may give negative effect on your search engine rankings.