"Annotate That! is a free unique annotating service. Share web pages, images or documents with others and add your comments using annotations. Simply click on the web page or medium to make your annotation."
(We Create Digital)
"Zotero is an easy-to-use yet powerful research tool that helps you gather, organize, and analyze sources (citations, full texts, web pages, images, and other objects), and lets you share the results of your research in a variety of ways. An extension to the popular open-source web browser Firefox, Zotero includes the best parts of older reference manager software (like EndNote) - the ability to store author, title, and publication fields and to export that information as formatted references - and the best parts of modern software and web applications (like iTunes and del.icio.us), such as the ability to interact, tag, and search in advanced ways. Zotero integrates tightly with online resources; it can sense when users are viewing a book, article, or other object on the web, and - on many major research and library sites - find and automatically save the full reference information for the item in the correct fields. Since it lives in the web browser, it can effortlessly transmit information to, and receive information from, other web services and applications; since it runs on one's personal computer, it can also communicate with software running there (such as Microsoft Word). And it can be used offline as well (e.g., on a plane, in an archive without WiFi)."
(Dan Cohen & Sean Takats)
"Emerald will soon be offering a unique peer-reviewed reading list service to all subscribers - Emerald Reading ListAssist, which will help users to make the very most of their subscription. This service will raise awareness of Emerald's cross-disciplinary content, coherently combining new research with more seminal papers, in a format which breaks down a subject by sessions, making it easily applicable to under-graduate or post-graduate courses or modules.
Created for students and lecturers by students and lecturers, Emerald Reading ListAssist aims to improve and support faculty workflow. The service also provides students with a high-quality research tool, helping to build information literacy and research skills. The rigorous academic construction of Reading ListAssist assures a high level of quality for the user; each list is peer-reviewed by subject experts as well as in-house reviewers to make sure it meets the highest quality standards."
(Emerald Group Publishing Limited)
[Note that this is a subscription-only service.]
"Organize, share, and discover research papers! Mendeley is a research management tool for desktop & web. You can also explore research trends and connect to other academics in your discipline.
Mendeley is used at, and endorsed by, some of the world's leading research institutions. Based in London, we are funded by some of the people behind Skype, Last.fm, and Warner Music."
(Mendeley.com)