DAVOS, Switzerland — Protesters in Moscow and Cairo fill public squares to demand representative government. Yet on the streets of Madrid and New York — or of Athens, which gave us the very word for democracy — discontent is almost as rampant.

The only consistent messages seem to be that leaders around the world are failing to deliver on their citizens’ expectations and that Facebook, Twitter and other social media tools allow crowds to coalesce at will to let them know it. This is not a comforting picture for the 40 heads of state or leaders of governments who are attending the World Economic Forum here, including such disparate leaders as Chancellor Angela Merkel of Germany’s multiparty democracy or Meles Zenawi, the prime minister of the authoritarian state of Ethiopia.

“I think that what we have learned in the last few years since the financial crisis and since the Arab Spring is that brittle states with limited political and economic capital are particularly susceptible to the combination of severe economic downturn and the communications revolution,” said Ian Bremmer, the president of Eurasia Group, a political risk consulting firm in New York.

“Those brittle states come in different flavors,” said Mr. Bremmer, who moderated a panel in Davos on Wednesday on the state of democracy. “Some are authoritarian, some of them are democratic.”