In order to scale, a governance system needs to be efficient, which means, among other things, having mechanisms for managing the attention of the collective. It needs to ensure the most important proposals get attention, that those proposals get attention from the right people or subgroups, and that the people in those subgroups are inclined to act in accordance with the interests of the greater majority. The mechanism built into Alchemy that addresses those challenges is called "Holographic Consensus”. It enables people to make predictions about which proposals will pass, and rewards them for making accurate predictions. Thus there is an incentive to sort through proposals and identify those that are high-quality and most aligned with the purpose of the DAO.
Boosted proposals are the proposals agents have staked GEN (the native token of DAOstack) on, because they think they will pass. These proposals then rise to the top of the landing page of the DAO on Alchemy.