From time to time Decentraland call on the community to vote on important decisions. All voting takes place using Decentralands Agora tool.
Visit the tool here: https://agora.decentraland.org/
Currently, each vote is weighted on the amount of MANA you hold in your wallet. If any MANA is removed from the wallet used to vote, prior to the vote ending, then the vote will be void, and removed from the final result.