If you are involved in research of any kind, or if you have students who are required to work on research projects, you may want to check out Zotero. This Firefox extension is an incredibly powerful tool that helps facilitate the process of collecting research online, cataloging articles and other resources, adding notes and annotations to those sources and creating accurately formatted bibliographies that can be inserted directly into your writing. They have a great introductory tutorial you can watch to learn more about this amazing tool.
It is a bit like Google Notebook but Zotero takes things a step further by scaffolding the researcher in the process of organizing information and resources. You can quickly save articles that you find online into different folders based on their content and concentration. A single article can be associated with multiple folders in case it has relevance across different areas. You can add notes, summaries and other information for each resource you save much like in Google Notebook and desktop based tools such as Endnote. When you are all finished with your research you can export a bibliography in any of the major formats/styles and put that directly into your Word document or even Google Docs.
Currently it isn't possible to share or sync your Zotero library across computers so you are limited to working on the same computer but they are piloting Zotero 1.5 Sync, which purports to allow you to sync your data in this fashion and that will definitely make this tool even more user friendly. There are many other interesting upgrades in the works for Zotero 2.0 that include the ability to share your data and collaborate with others and the option to create a RSS feed from your bibliography.