Analysis: How social media sites were a key battleground in the Dublin Bay South by-election

The campaign was contested vigorously online with parties using increasingly sophisticated tactics to promote their candidates and attack rivals

Lynn Boylan, Sinn Féin’s candidate pictured with party leader Mary Lou McDonald, spent the most on online ads in the past month. Labour’s Ivana Bacik looks set to claim the seat after tallies. Picture: Leah Farrell/RollingNews.iie

Sinn Féin spent three times its nearest rival in the Dublin Bay South by-election on online ads in the past month.

According to the Facebook Ad Library, €12,436 worth of Facebook and Instagram ads were targeted to Dublin based voters promoting its candidate Lynn Boylan as of last Monday.

Labour’s Ivana Bacik was the second most promoted candidate, spending €4,499.

This was followed by €3,433 worth of ads promoting Fine Gael’s candidate James Geoghegan, ...