I've been pleased with Memex WorldBrain, which was recently demonstrated here on HN: you can annotate or star your pages, and every page starred/bookmarked, or

I've been pleased with Memex WorldBrain, which was recently demonstrated here on HN: you can annotate or star your pages, and every page starred/bookmarked, or visited for some seconds is searchable. If you do a web search on DDG, your Memex results also pop up at the same time.