On Instagram, Derek Luke’s life looks pretty sweet. The feed @IAmDerekLuke, which says it’s the “official” account of the “Empire” actor, shows him hanging out with his family in his hometown, posing with his nephew, saluting friends after their Oscar wins and giving a birthday shoutout to his favorite rapper, Biggie Smalls.

There’s just one problem: Luke doesn’t have anything to do with the account.

“Someone is trying to mess with my life,” he said of the Instagram feed in an interview with “Access Hollywood” last month. He complained to the anchors that whoever is behind @IAmDerekLuke had gone beyond simple fan antics, inviting followers to attend fake auditions and announcing the birth of a nonexistent child.

After almost six months of posting photos of Luke without his permission, the imposter account has amassed 78,000 followers, many of whom don’t appear to realize the photos aren’t endorsed by the actor. Even the “Access Hollywood” hosts didn’t know @IAmDerekLuke was fake before the segment.

The account attracts thousands of likes and comments. Especially popular are posts about social justice issues and photos of the actor posing with fans. Many praise @IAmDerekLuke for its apparent down-to-earth accessibility. “We need more actors like you who remain just ordinary people,” one fan wrote.

@IAmDerekLuke posts a personal photo of the actor at home with his family.

The birth of celebrity impersonators on social media coincides with our mass adoption of the medium. There are fake Twitter profiles for Will Ferrell (@WillFerrell), Tina Fey (@tinafey) and Jon Stewart (@itsmejonstewart). At one point Buzzfeed tallied 36 Twitter parody accounts for Bill Murray. The best of these are both witty and obviously fake. (All hail @KimKierkegaard, a mash-up of observations from Søren Kierkegaard and Kim Kardashian, and @SwiftOnSecurity, a vault of cybersecurity tips in the voice of Taylor Swift.)

But it’s not always so easy to root out the problematic imposters. When a Twitter exchange between Nicki Minaj and Taylor Swift can become the subject of national debate, knowing who’s really posting — or who really isn’t — matters.

Part of the draw of sites like Twitter and Instagram is the option of anonymity — a tenet that’s central to the founding philosophy of the web. Facebook is one of the only social platforms with an anti-pseudonym policy — and it faces a constant backlash from people who don’t use their legal names professionally, like drag queens, or people who avoid disclosing their identities for their own safety.

The user policies at both Twitter and Instagram prohibit posing as someone else without providing an obvious clue-in for readers that the account is fake, and both sites give explicit descriptions of the difference between parody and impersonation. Many parody sites contain a clear disclaimer, like @BillMurry, whose Twitter bio reads “I AM NOT BILL MURRAY. This is a parody account.”

But anonymity — along with the size of the user base — makes enforcing these policies a monumental undertaking. You can fill out a form to report a violation, or file a lawsuit, which might get the account taken down quicker.

Or you can take matters into your own hands, though this won’t always solve the problem either. In July, model, actress and singer Amber Rose took to her Instagram account to distance herself from a malicious Twitter account that was using her name. The account, @DaRealAmberRose, had made headlines cyberbullying Caitlyn Jenner and calling Drake a “fugly slut.”

“I’m not a mean girl and I don’t jump on the bandwagon of bullying ppl AT ALL especially when the whole world is against them,” Rose wrote on Instagram.

As of this writing, the fake account is still up.

I tried to get in touch with the creator of @IAmDerekLuke to find out what had prompted him or her to pose as Luke. But when I posted a comment that included my contact, Instagram marked it as spam and temporarily suspended my account. The situation seemed akin to real life celebrity: @IAmDerekLuke is tantalizingly public but still inaccessible.

It’s not hard to imagine why someone would impersonate a celebrity online. Creating a fake account is the easiest way to experience that person’s prominence, to feel heard among the cacophony of voices online.

“In a world where the most important currency is attention, celebrities are the real winners,” said Judith Donath, who studies how social networks affect behavior at the Berkman Center for Internet & Society at Harvard. “If you create an account like this, you’re able to gather an audience that thinks that you’re that person and they’re following your every word.”

Slipping into a celebrity’s voice to spew vitriol could also be a way of defaming that celeb — or a way of elevating a troll’s own words. “If a random unknown person says something nasty, it’s shocking. It seems very shocking if it’s coming out of the words of a known person,” said Donath.

Impersonators may have even more sinister motives. Take Robert Hunter, a 35-year-old man who was sentenced to 14 years in prison after using a fake Justin Bieber Facebook account to collect over 800 videos of teenage girls stripping for him on Skype. Still worse? He’s not the only one to use the scheme.

Pressure from celebrities led California to update its penal code in 2010 to specifically criminalize impersonation on the Internet. The law states that posing as a celebrity “for the purposes of injuring, defrauding … deceiving another person, or of obtaining a benefit” is a misdemeanor, punishable by a $1,000 fine or up to a year in prison.

While the California law is stricter than that of most other states, there’s still room for interpretation as to when it has been violated.

“The law is not entirely clear,” Mark Lemley, a professor at Stanford Law School and director of Stanford’s interdisciplinary program in law and technology, told The Huffington Post. “A fake account that actually pretends to be the real person in order to deceive others likely violates the right of publicity in most states. To be criminal, there would have to be actual fraud or other misbehavior, not just posting pictures.”

Celebrities increasingly use Instagram to share behind-the-scenes photos.

On Twitter, verified badges generally keep us from taking fake celebrities too seriously — and have become a point of pride that you’re the kind of person whom someone might bother to impersonate. The dating app Tinder recently rolled out verified accounts under pressure from its celebrity users. But it’s trickier on Instagram, which only started verifying in December 2014. Major celebrities who use the app — including Katie Holmes, who has been posting for almost six months — are still unverified. An Instagram flack told me that the company prioritizes celebrities or brands that have a high likelihood of being impersonated. The company provides a form through which fake accounts can be reported.

Derek Luke’s manager confirmed that the actor’s team is trying to get the imposter account @IAmDerekLuke taken down.

In the meantime, this particular fake account is probably not hurting his career.

While Luke posts only sporadically to his Twitter account, the fake Instagram account is killing it. Last week, the African-American actor faced a torrent of abuse online for his interracial marriage to Hispanic actress Sophia Adella Luke. The fake Luke posted a stirring rebuttal to the critics: “My wife may not be Black but she is mine.” The post was picked up by Cosmopolitan, the Daily Mail, Fox News and here at The Huffington Post.

@IAmDerekLuke’s comment on his marriage drew accolades from the press.

You can’t pay for publicity like that.

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