Google has a page in its Webmaster Tools help center addressing the question: Can competitors harm ranking? This has been a topic getting a lot of discussion since the Penguin update. It was getting a pretty good amount before then too, but it seems to have ramped up significantly in recent months.
Some webmasters have noticed that Google has updated the wording it uses to address this question on the help center page. There are various forum discussions going on, as Barry Schwartz at Search Engine Roundtable has pointed out.
Back in 2006, Schwartz posted what Google said on the page at the time, which was:
There’s almost nothing a competitor can do to harm your ranking or have your site removed from our index. If you’re concerned about another site linking to yours, we suggest contacting the webmaster of the site in question. Google aggregates and organizes information published on the web; we don’t control the content of these pages.
Our search results change regularly as we update our index. While we can’t guarantee that any page will consistently appear in our index or appear with a particular rank, we do offer guidelines for maintaining a “crawler-friendly” site. Following these recommendations may increase the likelihood that your site will show up consistently in the Google search results.
These days, it just says:
Google works hard to prevent other webmasters from being able to harm your ranking or have your site removed from our index. If you’re concerned about another site linking to yours, we suggest contacting the webmaster of the site in question. Google aggregates and organizes information published on the web; we don’t control the content of these pages.
Apparently the wording itself was changed in March, though the page says there was an update made on 05/22. Either way, Google recently changed it, and instead of saying “there’s almost nothing a competitor can do to harm your ranking…” Google now says, “Google works hard to prevent other webmasters from being able to harm your ranking…”
That’s not incredibly reassuring.
Google has also added the following video from Matt Cutts to the page:
This video isn’t exactly an answer to the question though. It’s more about telling on competitors’ black hat tactics, rather than your competitors directly hurting your ranking. Essentially, it equates to: file a spam report.
Rand Fishkin at SEOmoz has been testing the negative SEO waters, challenging others to hurt his sites’ rankings. He told us a couple weeks ago that despite thousands of questionable links, his sites were still ranking well.