"We know one of the most successful forms of e-learning is collaborative learning done online through social interactive discussion. Weblogs build off of this successful model as a dynamic form of e-learning content and an engaging e-learning experience." - from Blown Away by RSS Feeds & Blogs by Paul Stacey (2003).
Blogs (aka weblogs) take many forms, but a blog typically resembles an online diary - except that entries need not be of a personal nature and that there are usually many links to other online content (e.g. other blogs). Collaboration happens through blogs in at least five ways:
Many blogs have a facility for readers to post comments.
Some blogs are co-authored.
Many blogs have a prominent list of links to 'like-minded' blogs (also called blog-rolls).
Many blogs have a facility for syndicating their content to other blogs through automated systems such as RSS (see also the section in this book on Syndication via RSS).
Perhaps most importantly, there is a strong culture of blogs commenting on (or re-circulating) material from other blogs.
Different blogging tools (see the section on blogging services) differ in how well they support these different forms of collaboration - e.g., LiveJournal is (apparently) good at encouraging the creation of small circles of friendly blogs. There is also a generic tool (Trackback) that facilitates such connections (see also the section on Trackback).
There is another useful intro article by James Branum. It gives a fairly comprehensive background to blogging from a journalism perspective, together with an overview of how various mass communication theories might apply to blogging.
Blogging across the curriculum by Pattie Bell Hastings is a good, nicely organised set of information on the hows and whys of blogging - suitable as a resource for a course in which students are expect to blog.
James Farmer links to a number of good example of how blogs are being used in education and in a follow-up article provides an overview of what seems to be working and what not.
Scott Leslie (2003) has drawn up an interesting matrix of uses of blogs in education - and asks for comments here. The matrix is divided into four quadrants with writing at the top and reading at the bottom, and students on the left and instructors on the right. Scott acknowledges that this might skew things to more formal learning situations, but given this provides a useful framework for thinking about what blogs can be used for in education.
The University of Minnesota's Uthink system (based on Moveable Type) makes it easy for staff and students to start their own blogs - both individually and in groups.
Portfolios are not usually thought of as collaboration tools, but when they are posted on an intranet or the internet as electronic portfolios they open up spaces for collaborative work. A good intro article on electronic portfolios (including a large listing of portfolio tools) here.
Similarly, learning journals, are usually seen as individual learning tools, but can equally be used in a collaborative online environment. An article on Journal writing as an adult learning tool by Sandra Kerka discusses issues such as privacy and evaluation, leaning towards saying students should feel free to write about private issues and to criticise the course/lecturer without fear of lecturer evaluation. In an online journal privacy is of course not possible, but the constraining effects of evaluation may be reduced by having it occur in the context of a community of learners who read and comment on each others' journals - rather than one-sided lecturer evaluation. Kerka also discusses various dimensions on which journals could be evaluated.