The Google Sitemaps team has clarified that links from bad neighborhoods do not harm a site's rankings, only links to bad neighborhoods. The clarification goes against conventional thinking which assumes that links from bad neighbourhoods harm as much. Vanessa Fox has clarified about the difference between natural and unnatural links.
Natural links are links to your site that develop as part of the dynamic nature of the web when other sites find your content valuable and think it would be helpful for their visitors. Unnatural links are links to your site placed there specifically to make your site look more popular to search engines. Some of these types of links are covered in our webmaster guidelines:
- Don't participate in link schemes designed to increase your site's ranking or PageRank. In particular, avoid links to web spammers or "bad neighborhoods" on the web, as your own ranking may be affected adversely by those links.
- Avoid "doorway" pages created just for search engines.
In general, linking to web spammers and "bad neighborhoods" can harm your site's indexing and ranking. And while links from these sites won't harm your site, they won't help your indexing or ranking. Only natural links add value and are helpful for indexing and ranking your site.
Even Matt recommends the use of the "nofollow" link attribute to safely purchase links purely for traffic purposes. The Webmaster guidelines also offers a few tips regarding this-
- Avoid "cookie cutter" approaches such as affiliate programs with little or no original content.
- If your site participates in an affiliate program, make sure that your site adds value. Provide unique and relevant content that gives users a reason to visit your site first.