A month ago, Google enabled starring of items in Google News. Now, they're extending that same feature to the main Google search. Items starred sync with Google Bookmarks and the Google Toolbar.
Starring will replace SearchWiki, which enabled users to promote selected results to the top or nix other results altogether. Google said they found that people like marking items they liked, but they did not like altering organic results. These actions taken in SearchWiki only affected a user's personalized search. The same is true for starring.
One feature about SearchWiki that starring does not replace is annotations. Google is encouraging users who like to annotate to instead use Sidewiki. By the way, Sidewiki is not just relegated to personalized search - it's public.
Image via Official Google blog