Rap Genius, a rap lyrics startup that inexplicably managed to raise $15 million last year, has been blacklisted by Google. Google allegedly caught Rap Genius trying to manipulate its search rankings by rewarding third parties who link to its content. As a punishment, Google has demoted Rap Genius in its search results, leading to a precipitous decline in traffic.

Google is just the latest in a long list of people, companies or other entities who have had beefs with the lyrics site. The company and its outspoken founders have a habit of rubbing people the wrong way. Here are just a few of the many examples.

Mark Zuckerberg. The Facebook founder was hanging out at the home of billionaire Rap Genius investor Ben Horowitz with the rapper Nas when Rap Genius co-founder Mahbod Moghadam snapped a photo of the trio and posted it online. Zuckerberg, who (ironically) closely guards his privacy, demanded that Moghadam take the photo down. Moghadam complied, and apologized to Zuckerberg. But then he gave an interview where he proclaimed that "Zuck can suck my d**k." Moghadam now blames a brain tumor for his behavior.

The National Music Publishers Association. The Rap Genius business model is to post song lyrics online and then let users (including, in some cases, the artists themselves) annotate them. This is done without the approval of the holders of the songs' respective copyrights, and that has gotten the NMPA, which represents many of those copyright holders, up in arms. The site received takedown notices from the organization last month. Rap Genius responded that "we can't wait to have a conversation with them about how all writers can participate in and benefit from the Rap Genius knowledge project" and described Rap Genius as "so much more than a lyrics site." Rap Genius is now reportedly negotiating with the NMPA to become a licensed user of the publishers' lyrics.

Heroku. Heroku is a cloud computing platform that's popular with Silicon Valley startups. Rap Genius is a Heroku customer, and last winter Rap Genius developer James Somers wrote a blog post arguing that Heroku had "swindled its customers" by making technical changes that make Rap Genius work less efficiently on the platform. Heroku said it was listening to customers concerns, but Rap Genius co-founder Tom Lehman wasn't satisfied, telling VentureBeat that Heroku was still misleading customers.

Warren Buffett. According to Betabeat, back before he founded Rap Genius, Moghadam wrote a satirical memo to "the Ballstate Insurance Company." Allstate was a client of the law firm of Dewey and LeBoeuf, which had offered Moghadam a job but then asked him to take a less-highly-paid "deferral" during the tough economic client of 2009. During that deferral, Moghadam was scheduled to do an unpaid internship at Warren Buffett's company, Berkshire Hathaway. Berkshire noticed the blog post and alerted Dewey, which counts Allstate as a client, and Moghadam lost both the Berkshire internship and the Dewey job. Apparently, Moghadam is still bitter about the incident. A Feb. 21 tweet from the official Rap Genius account invited Buffett to perform a sexual act on the company (we're a little unclear on how that would work). Soon afterwards, Moghadam told Betabeat that Buffet was "a little b**ch."

Correction: the original version of this post mis-stated the relationship between the Dewey law firm and Warren Buffett. We regret the error.