Sept 13 (Reuters) - As the main contenders in the race to succeed Angela Merkel as Germany"s next chancellor faced off in a televised debate on Sunday night, their political parties deployed social media teams in a parallel battle online. None of them, though, could match the impact of cyber-savvy activists holding them to account. While conservative Armin Laschet, Social Democrat Olaf Scholz and the Greens candidate Annalena Baerbock traded barbs in the studio, strategists and professional campaign staffers took to Twitter (TWTR.N) to attack, defend and fact-check each other, hoping to make their hashtags trend and talking points stick. Yet Luisa Neubauer, a 25-year-old organiser in the student climate movement Fridays for Future trumped the campaigners" efforts to go viral with her question: "And what exactly has prevented the grand coalition at any point in the last eight years from credibly giving the impression that they had an interest in ending the climate crisis?" Neubauer was referring to a coalition government of Merkel"s Christian Democrats (CDU) and Scholz"s Social Democrats (SPD) that has run Europe"s largest economy for the past eight years. By Monday, her tweeted question had garnered some 8,500 likes and over 850 retweets. With climate change an issue that resonates the most with young voters, other activists were also getting the attention. For example, Jakob Blasel, 20, a Greens candidate, got nearly 4,000 heart-shaped reactions after tweeting: "Are you also as shocked as I am by how quickly the existential threat to our livelihoods was simply shrugged off?" While some individual politicians" posts scored better, parties" official accounts fell far short of such metrics. One of the most successful tweets of the night from CDU"s official account was a short video showing Scholz, who is also finance minister in the coalition government, denying his ministry had been targeted in an anti-money-laundering raid combined with news headlines contradicting him. That video, tagged "Aha", got fewer than 280 likes. For the SPD, which leads the conservatives and Greens in polls ahead of the Sept. 26 election, most tweets from its official account averaged fewer than a hundred likes. [USN:L8N2QD0JD] The coronavirus pandemic has boosted online activity, including election campaigning, but political scientists say the impact of social media on voting preferences remains a relatively poorly understood phenomenon in Germany. Political consultant and social media expert Martin Fuchs says the flurries of tweets with party talking points during televised debates primarily target journalists, who are then expected to pick them up in their coverage. This way, voters who are not active online can be still be reached via traditional media. "Twitter remains a niche medium in Germany," Fuchs told Reuters, saying most active users are in the media and political bubbles. While the understanding of digital culture has grown considerably over the past two years, many aspects remain "very amateurish," Fuchs said. "And interestingly enough, more physical campaign posters have been put up this year than ever before."