South Korea's president emerged as the unlikely star of Seoul's mayoral elections last week, but in a way he could not have dreamed of - as the butt of satire in a wildly popular podcast that helped end his party's grip on the country's capital.

Conservative 69-year-old Lee Myung-bak is the main character in Naneun Ggomsuda or I am a Sneak, a podcast that satirized his government and which has been downloaded by six million people since it was launched in April.

It is South Korea's most popular download on Apple's iTunes store and has been credited with turning out voters in their 20s and 30s in huge numbers at the election, in which the government was handed a sobering defeat at the hands of a left-wing activist.

The president we praise is a president who loves the people, a president who loves farmers and the working class, begins one section of the podcast.

Although he is the Korean president, his love of farmers and workers is only for Americans.

While South Korea is known mainly to the outside world as an Asian industrial juggernaut, unease over widening income gaps, higher prices and youth unemployment has been rising.

Conservative rule and the big-business friendly policies of the government are no longer in fashion, leaving elections next year for a new president and parliament hanging in the balance.

South Korea's close ties with the United States and a free trade agreement, signed in Washington last month but stalled in the local parliament because of the effect it will have on small businesses and farmers, have come in for particular criticism.

Dubbed a tribute to the president the regularly updated podcast is the brainchild of four men including Kim Eo-jun, the publisher of an activist Internet newspaper.

Those in their 20s and 30s feel attached to us because we talk politics in terms they can relate to, Kim told Reuters after a meeting of nearly 3,000 fans of the broadcast this weekend where they celebrated the surprise victory of activist Park Won-soon in the Seoul mayoral election.

An independent with no political base, Park was picked to run against an established politician from Lee's Grand National Party (GNP), also a lawyer, but only after the disunited opposition failed to come up with a mainstream candidate.

He is a long-standing opponent of the trade deal with the United States and won despite wooden political performances on the stump and on television.

Naneun Ggomsuda, apparently, swung the vote in his favor.

I listened to the same clip four or five times. I kept clicking to update the podcast, said Park Jong-sang, a 37-year-old cartoonist attending an event organized by the authors of the podcast on Sunday. It became part of my life.

PRESIDENTIAL CANDIDATE

While Lee is barred from seeking re-election under South Korea's constitution, the GNP has a powerful candidate in the form of Park Geun-hye, the daughter of the country's assassinated dictator, Park Chung-hee.

A slight woman in her fifties, Park is the single most popular politician in South Korea and has dominated opinion polls with her brand of Korean Thatcherism since she entered politics.

She regularly commands 30 percent-plus in popularity polls and is the front-runner for the presidency. Belatedly, she has started building a presence on social media like Facebook.

Yet a month ago, her commanding lead was overtaken by a close friend of the newly elected Seoul mayor, software engineer and university professor Ahn Cheol-soo, who had not even declared his intention to run for the presidency.

The Seoul mayoral success may have opened the door for Ahn to run for the presidency against the favorite.

Park meanwhile has recently shifted to embrace more welfare friendly policies, although it may be too late. While official South Korean data shows that unemployment for those in their 20s is 4.8 percent, modest by the standards of the United States and Europe, a wider international benchmark from the United Nations' International Labour Organization puts it at 21 percent.

In this dire economy, people don't have confidence or trust in the government's ability to help them. Especially young people who, unable to see their way out of the ditch, will continue to listen to the show next year, said Lee Jun-han, a political science professor at Incheon University.

While the hosts of Naneun Ggomsuda are under investigation by police for spreading what government politicians say are unsubstantiated rumors, it has struck a chord in the world's most-wired country where 40 percent of the population uses smartphones.

The mainstream media is usually bland, and the weekend gathering signaled that the new medium and the message has started to resonate.

They swore a lot and blamed the current government, which mainstream media don't do or can't do, said Lee Hae-yeon, a 35-year-old office worker who says she listens to Naneun Ggomsuda traveling on the subway.

I think they will do their best to criticize until this administration or the conservatives lose.

(Editing by David Chance and Raju Gopalakrishnan)