More than 90,000 gathered in Taiwan's capital on Saturday to press their demand for the president to step down.
The calls follow a string of scandals involving relatives and aides of President Chen-Shui bian.
"Depose" was the message being conveyed by many of the participants who have vowed to see through their demands.
The movement is led by Shih Ming-teh, who spent more than 25 years in jail when Taiwan was under martial law.
The "thumbs-down" - as well as the red attire to symbolise anger - have become trademarks of the movement.
Many braved heavy rain overnight before returning on Sunday to keep up their protest.
In a good-natured gesture, protesters offered the protection of their umbrellas to the police.