Although Cóir's striking advertising campaign has been widely noticed and commented upon – and inspired one complaint so far to the Advertising Standards Authority – advertising experts are divided as to whether it will be effective in the long run.

"In political campaigns, marketing and advertising is of huge importance. But it has to be much more than just putting up a poster on a pole," says Niall McGarry, chief executive of Impact Media. "In the past these political campaigns used to be a much more straightforward procedure. Now it is more complex and must operate on many more different levels to succeed."

According to McGarry, Cóir, which warns of a €1.84 minimum wage on one of its posters, should take marketing lessons from a ghost of the past – Libertas.

"Libertas went down the road of shock tactics and one-liners on posters in their campaign during the first referendum and now for the second they are disbanded. This is important to remember. If a party or campaign goes with a line that is open to interpretation or ambiguous in any way it can be picked up on and torn to shreds either now or a few years down the line."

But McGarry also points out that the Yes campaign has its own battle on the opposite end of the spectrum in relation to its advertising. "It is possible that campaigns can be too vague. It can be a big problem. The first No vote in Ireland came about because of a complete lack of understanding and this time being open and clear is the issue again. There is a balance that needs to be struck," he says. "What Irish people need in these campaigns is clarity. Anything else will just come across as shallow ideals."

JP Donnelly, chief executive of advertising agency Ogilvy, wonders whether Cóir's message is being heard at all in its insistence on hard-hitting marketing.

"Theirs is a very specific kind of campaign, but in the barrage of statements I would wonder if they are actually getting their message across."

Donnelly says that the advertising campaigns for both Yes and No can go two ways. The first is that both of their marketing and advertising campaigns can get a very clear message across and this, says Donnelly, works very effectively. The second is that it will "add noise to a debate and then muddy the waters leading to distrust. Cóir in particular operates a guerrilla form of advertising, and this can prey on the doubts existent in people's minds."

"There is an issue that it is not a balanced enough approach on Cóir's behalf. It is not a case, as it was with the advertising and campaign of Barack Obama, that the leader and the politics are one and the same thing. It is an ad hoc campaign and it is much harder to push that," says Donnelly.

Counter-advertising is a phenomenon which has been evident in the back and forth between Yes and No. Mere days after Cóir erected its controversial posters, an online 'lie-buster' was advertised by pro-Lisbon movement Generation Yes.

"Counter-advertising between the Yes and No sides on the Lisbon Treaty is probably the most high-profile example of this form of marketing and I feel that, while it can cause confusion and cloud the issues, it is also a healthy phenomenon." says Mark Hopkins, managing director of his own advertising agency Hopkins Communications.

And the counter-attack marketing approach of the two sides has never been more evident. When contacted, Generation Yes said: "The Irish people deserve an honest debate on this treaty. We don't believe in attacking people personally, but we have zero tolerance for anyone who lies to the Irish people in this campaign. When people make false statements, we will respond immediately with the truth through the 'Fight the Lies' section on our website," said spokeswoman Sharon Waters.

In response, Cóir maintains: "The only complaints we have had are from politicians and Yes campaigners. Most voters say one or more of the poster messages made an impact on them."