By Angela Alcorn on the blog MakeUseOf, October 8 2010; shared by IdealWare in their Best of the Web email, May 8 2012. The post offers some tips, links to tutorials, and then 10 free tools, with brief annotation to describe what each is good at.
From their "Pinning 101" notes, Pinterest is an "online pinboard." The explicit purpose is to bookmark and share images from the web, and to annotate them. While the site emphasizes "beautiful" things from the web, with a suggestion of domestic purposes, this might be another way to generate collaborative collages (as we've done with GSCC) or to share non-written artifacts on a specific topic.
This is a free service of the Qualitative Data Analysis Program (QDAP), maintained by Texifter. (See QDAP tag) . Tools in this toolkit facilitate coding of text data sets, enable annotation with shared memos, and provide tools to assist with managing team collaborations (permissions, etc.)
Mendeley is both a (free) reference manager and an "academic social network." Users can import papers they are using for research, highlight, annotate, and tag them. Mendeley will provide an appropriately formatted citation for the paper. Additionally, users can search the citations (and descriptions) of papers that others have contributed to Mendeley, as well as creating and joining groups with like-minded researchers.