Rap Genius has apologized for using questionable SEO tactics to ramp up its Google search results. In an open letter published on its blog, the lyric annotation website acknowledged that its search traffic success is in part due to a strategy that is not fully compliant with Google's terms.

"tl;dr: We effed up, other lyrics sites are almost definitely doing worse stuff, and we’ll stop. We’d love for Google to take a closer look at the whole lyrics search landscape and see whether it can make changes that would improve lyric search results," Rap Genius' founders wrote.

The open letter went up after a blog post outing the site's spammy tactics was published by tech entrepreneur John Marbach. The post includes an email from Rap Genius co-founder Mahbod Moghadam that blew the lid off the site's reliance on SEO manipulation, or "growth hacking." Moghadam apparently told Marbach to embed a prospective Rap Genius post with links to Justin Bieber's latest album, a move that would be sure to rake in "MASSIVE traffic."

According to Marbach, "Their business depends on their search engine ranking position (SERP's) on Google. Hyperlinks connect the web and determine SERP's. Thus, the most powerful weapon RapGenius can deploy is a series of powerful hyperlinks. You can see in Mahbod's email that he is asking for hyperlinks from high-page rank sites (personal blogs) with anchor text that mentions tracks from Bieber's most recent album."

It's apparently such an issue that Matt Cutts, Google's head of search spam, said his team was "aware" of Rap Genius' shady tactics and is "looking into it."

[via Valleywag]