I often get requests for me to add links to my sites. Usually it is just someone looking for something simple that will deliver them some relevant traffic.
What I have found though is that one should ALWAYS verify that the link destination is okay. It should not be in a bad neighborhood. In addition, it should not link out to bad neighborhoods. These bad neighborhoods will get sites that link to them penalized in the search engines. That’s right – the sites that you link to can get your site penalized. Not only that, but the sites THEY link to might get your site penalized.
The link below has a bad-neighborhood checker. It will scan a URL and determine if there are questionable links. Then it will scan the linked to pages to see if any of their links are questionable in nature. It’s a great little tool and I highly recommend using it.