It is not unusual for webmasters to tweak anchor text in order to either diversify anchor text or change keywords for higher SEO value. But SEOs might want to take the extra time and ensure the anchor text is correct from the start, as well as stop the practice of sending emails requesting anchor text be changed on other sites (or change that anchor text within your own backlink network), because it seems that Google views changing anchor text as suspicious and a reason to trust a link less.

Pedro Dias, who was a member of the search quality team at Google for over five years, tweeted:

Dias was with Google’s Search Quality Team from 2006 through 2011.  And whenever a former member of the search quality team tweets something SEO-specific, it is worth paying close attention, especially for SEOs who are looking for the tiniest advantage over their competitors.

If anchor text changing is a factor in how valuable a link is in the eyes of Google, then SEOs need to consider the impact that changing anchor text on older links will have.  In fact, it seems as though as soon as it is crawled, Google registers the anchor text in such a way that if it is changed anytime after that, the trustworthiness of that link will go down.

When pressed further by Barry Schwartz of SERoundtable, Dias wouldn’t confirm it was from his time working at Google, but said

And that is almost a confirmation in itself, and confirmation enough for many SEOs who noticed the exchange on Twitter.  That said, it is surprising that he would tweet something that could have significant impact in the way SEOs (and spammers) handle their backlink anchor text.

It also seems that perhaps site reputation with the link might play a role in it – changing anchor text on a very trustworthy site might not be hindered or devalued, but one from “Joe Webmaster’s Blog” could see that link devalued much more if the anchor text is changed.

While some SEOs employ a “get the link then ignore it” policy, others will constantly tweak anchor text to throw new keywords into the mix, to diversify anchor text, especially on older links, or just to optimize all their anchor text so it as close to the “sweet spot” as possible.

This also opens up potential for a new kind of negative SEO, where competitors will contact sites to request anchor text be changed, knowing that to Google could potentially value that link less. With many competitors already getting links removed from sites, this could be a way to devalue your competitor’s links without it raising red flags unless those competitors also happen to track all the anchor text too.

When Dave Naylor mentioned the negative SEO aspect of it, Dias said…

Of course, as SEOs know, never underestimate a spammer with time on his hands and competitors to burn.

Unless Google comes straight out and say that anchor text being changed does not have any impact whatsoever on the value and trustworthiness of a link, SEOs should stop tweaking and updating any anchor text on all backlinks, as a non-optimal anchor text backlink is more valuable that one that has been changed after the fact to better anchor text.