I use Power Note all the time. It is a bookmarking and note-taking app. You also can save images from the web and take notes by speech. What's awesome is that you can access your bookmarks and notes anywhere. Power Note is powered by Diigo, a web highlighting (highlight excerpts of web articles and save it online) and bookmarking service where you can share what you find. I haven't used it's collaborating capabilities yet but it looks promising. And if you want you can choose to have public or private notes/bookmarks. Also it's great for organizing notes and making lists by using tags (which I don't use too much) but it helps when looking for specific notes from a long time ago.
I've been using it for over a year now and I haven't had any complaints about it. It has served me well.
Wow, I feel like I work for them giving all that info.