Many webmasters think that low quality links or links from spammy websites can have a negative effect on the ranking of their websites on Google.
The problem with links from spammy websites is that it is very difficult to do something against them. For example, a competitor could add your website to a link farm network or the competitor could spam with your URL
Google has released an official statement about spammy links
This month, Google published an official statement about low quality links in their webmaster blog. Here are the main statements:
Linking is a significant factor in Google's ranking algorithm but it is just one of many factors. Other factors are the content of your web pages, the site structure and the appearance of a keyword in the different web page elements.
If you have a high quality website and get links from spammy websites, try to contact the website owners and ask them to remove their links. Google will not help you with that.
It the webmasters of the spammy website are not cooperative, don't worry and focus on the links that are under your control.
Google says that low-quality links rarely stand the test of time and that they may not be considered by Google's ranking algorithm.
If you want to make sure Google knows about the spammy links and is valuing them appropriately, you can report them to Google with their spam report or paid links report forms