This experiment lets you influence your search experience by adding, moving, and removing search results. When you search for the same keywords again, you’ll continue to see those changes. If you later want to revert your changes, you can undo any modifications you’ve made. Note that this is an experimental feature and may be available for only a few weeks.

This is something that can bode for good or ill. I’d be surprised if this rolled out across the board without a serious review process related to its beta period. The possibility for search engine results to be gamed seems too massive to ignore, like a sumo wrestler crammed into a phonebooth.