When President Obama sent his first Twitter post on Monday, he attracted a world of attention.

The tweet: "Hello, Twitter! It's Barack. Really! Six years in, they're finally giving me my own account" has been retweeted or favorited more than half a million times.

Within five hours, the @POTUS account had racked up 1 million followers, breaking a record set by actor Robert Downey Jr., according to the Guinness Book of World Records.

But it wasn't just fans who wanted to follow the president. Within minutes of that first post, the @POTUS account was barraged with replies filled with racism, personal attacks and troubling imagery.

One of the first, from an account that has since been suspended, addresses the president as the N-word and advises him to "get cancer."

A post by a Twin Cities man included a doctored image of Obama's famous campaign poster. In this version, the president's head is in a noose, his eyes closed, head cocked to the left as if he'd been lynched. The word "ROPE" replaces the word "HOPE."

The post on Monday afternoon by @jeffgully49 includes the message "#arrestobama #treason we need 'ROPE FOR CHANGE' " The account 's profile photo features a photo of Obama behind bars. "We still hang for treason, don't we?" the post read.

The writer, Jeff Gullickson of Minneapolis, is unapologetic, despite the fact that he said the tweet earned him a visit from the Secret Service.

Gullickson has shared several other images of Obama being noosed since then, and in replies to others who have questioned him on Twitter, he insists the post was not racist.

On May 19, in a response to a tweet from radio host Montel Williams, Gullickson responded: "why? It's a meme. Are you offended? You should be offended that a treasonous communist is president than my lil vote. Geez"

The Secret Service has a special Internet Threat Desk that monitors posts, assessing whether they constitute actual danger.

Speaking to the New York Times, Secret Service spokesman Brian Leary said: “People have the right to free speech. We also have the right and an obligation to determine a person’s intent when they say something.”

Law enforcement officials can submit requests to Twitter when postings appear to post a danger to someone, and Twitter users themselves often attempt to self-police the service. After @jeffgully49’s post, several users posted tweets about him, flagging the @Support and @SecretService Twitter accounts.

When reached for comment by the New York Times, Gullickson responded by asking in an email how much he would be paid for an interview.

By Friday afternoon, one Twin Cities company was swept up in the drama. Loffler Cos., based in Bloomington, released a statement clarifying that an employee by the same name was most definitely not the Jeff Gullickson who posted the tweets.

STAR TRIBUNE STAFF