Women on Air, a group that campaigns for better gender balance on radio and television, celebrates its third birthday next Wednesday with a sold-out event at European Union House that will be addressed by Sinéad McSweeney, Twitter's European director of public policy.

Under the heading Stories Begin on Twitter, McSweeney (@smcs) will talk about Twitter's function as a "global town square" – a phrase that has been deployed regularly throughout 2013 by chief executive Dick Costolo and other senior executives at the IPO-filing social network.

"Our campaign began on Twitter where we highlighted the lack of female voices on radio and television, particularly on influential news and current affairs programmes," says Women on Air founder Margaret E Ward.

“The medium allowed us to increase awareness of the issue, gain members and support, publicise events and encourage radio and TV programmes to do more to find women to speak on all topics,” she says.

As well as maintaining a list of female expert contributors and promoting it to producers, the not-for-profit group has in its three-year existence secured training and other practical assistance from the Broadcasting Authority of Ireland and broadcasters including RTÉ, where management has been stung by criticism that it has ignored women's voices.

But, Ward adds, Women on Air (@WomenOnAirIE) would not exist without Twitter.