Held in the stunning Petrovaradin fortress, on a hill above the Danube, it hosted The White Stripes, Underworld and Fatboy Slim - and 50,000 ecstatic fans from all over the Balkans. They ringed the ramparts, moshed in the moat and crammed into 20 mini-arenas offering everything from drum'n'bass, reggae, rock and techno to jazz. Exit is now the largest festival in South-east Europe.
That's no mean feat for an event that began as a student protest again Slobodan Milosevic. Stars now flock to join the celebration of freedom by playing at Exit, among them Iggy Pop, Massive Attack and Cypress Hill. This year, Norman Cook said after playing to the packed crowd: "I have never been to Serbia before. The audience seemed the most up-for-it I've played to in the world, fresh and unjaded. I heard good things about Exit from other DJs. It's word-of-mouth recommendation, and that counts for a lot."
Carl Cox, who also played this year, said: "I heard of Exit from Pete Tong. He raved about it. I've played in Eastern Europe before, but not Serbia. Now it's their time to see acts like Underworld and Garbage." This year, Radio 1 covered Exit for the first time.
For me, broadcasting from Exit brought back memories of a visit I made to Eastern Europe, to Romania in 1990, after the long years during which the dictatorships shared a suspicion and hatred of Western rock and dance music. On that visit to Timisoara, just over the Romanian border from Novi Sad, the audience went nuts in a frenzied appreciation of music they'd been denied for so long.
Milosevic's regime was not as musically hard-line, but it wasn't welcoming. Fortunately, help was at hand in the shape of B92, the sort of idealistic pirate radio station broadcasters drool over. It doesn't claim to have brought Milosevic down, but its DJs encouraged demonstrations, played rebel music and exhorted the young to vote.
B92 started life in 1989 with a two-week licence, but just carried on. It was raided, taken off the air, reinstated, shut down again. Milosevic's aides termed its broadcasters "spies and terrorists". But, on B92, a generation of Serbs got to hear Clash-tastic music.
So, after Nato bombed Novi Sad in 1999, the youth of Serbia were ready to retaliate - with a 100-day protest party. Exit was born, bringing in musicians and DJs, holding parties on the river, around the castle and on boats.
Exit has now been whittled down to a more manageable four days. Radio 1 brought four shows to broadcast for the first time this year: myself, Annie Mac, Fabio and Gilles Peterson. The station's executive producer of live events, Jason Carter, said: "It felt the right time to introduce this event to a much wider UK audience."
This year the event earned its stripes in another way. Huge lightning storms raged above the castle, though the music totally drowned out the thunderclaps. Torrential rain drenched the crowd, and talk turned to that Glasto favourite - how to cope with the mud.
Annie Nightingale is on Thursday nights/Friday mornings, 1am-3am on Radio 1, and online at www.bbc.co.uk/radio1