A collaborative blog is a type of weblog which publishes posts written by multiple users. The majority of high profile collaborative blogs are based around a single uniting theme, such as politics or technology.

In recent years, the blogosphere has seen the emergence and growing popularity of more collaborative efforts, often set up by already established bloggers wishing to pool time and resources to both reduce the pressure of maintaining a popular website and to attract a larger readership.

Types

While every collaborative blog is unique they can typically be placed in one of two broad categories:

Invite only

An Invite Only collaborative blog is one in which a founder blogger personally selects a small group of co-bloggers, inviting them to contribute to his or her blog. The Invite Only blog typically focues on a single common interest subject - i.e. politics, legal issues or, occasionally, comedy.

For instance, in July of 2003 Chris Bertram established Crooked Timber, a collaborative Invite Only blog frequented by such established bloggers and academics as Kieran Healy, Ted Barlow and Henry Farrell, beginning with the introductory post:

Crooked Timber is a cabal of philosophers, politicians manque, would-be journalists, sociologues, financial gurus, dilletantes [sic] and flaneurs who have assembled to bring you the benefit of their practical and theoretical wisdom on matters historical, literary, political, philosophical, economic, sociological, cultural, sporting, artistic, cinematic, musical, operatic, comedic, tragic, poetic, televisual etc. etc., all from perspectives somewhere between Guy Debord, Henry George and Dr Stephen Maturin. We hope you'll enjoy the show.

Open invite

Conversely, Open Invite collaborative blogs allow any user to register for a blogging account, providing instant access. Perhaps the most famous of these blogs is DailyKos, a left-leaning collaborative blog founded in 2002 by Markos Moulitsas. DailyKos allows bloggers the opportunity to post their opinions on the site without pre-approval of the content.

Open Invite collaborative blogs succeed on the basis that the community acts to weed out trolls, spammers and other troublemakers. Much like online forums (and Wikipedia itself), the accessible nature of the Open Invite collaborative site is protected by dedicated moderators and fellow bloggers who will act quickly to quell any signs of spamming.

Advantages

For bloggers

In recent years the blogosphere has seen the emergence of many new Invite Only collaborative blogs, each accepting contributions from a group of established bloggers. While it may be unfair to ascribe this trend to any specific cause it is often the case that the pressures of maintaining a popular individual blog for an extended period of time can become too great, leading the successful blogger to naturally tend towards a lower pressure collaborative effort.

On well-known example of this phenomenon can be found at Protein Wisdom, a popular blog written by surreal conservative Jeff Goldstein. A much publicised incident in which Goldstein was harassed by University of Arizona adjunct lecturer Deborah Frisch - combined with various other real-life obligations - led Goldstein to retool Protein Wisdom as a collaborative site frequented by a number of guest posters while Goldstein partially withdrew. Today Goldstein blogs both at Protein Wisdom and the high profile collaborative blog Pajamas Media.

Collaborative blogs (particularly of the Open Invite variety) allow those without their own personal site (or those with poorly-trafficked sites) the opportunity to present their opinions to a much larger audience than they would typically have access.

For readers

A primary advantage for the readers of collaborative blogs is the simple fact that a collaborative effort typically make for a more regularly updated site. It is not unusual to find collaborative weblogs publishing new material 24 hours a day, allowing readers the opportunity to read new material on an almost constant basis.

Disadvantages

While Open Invite collaborative blogs encourage vibrant discussion on such subjects as politics and current affairs they unfortunately tend to attract bloggers who are more interested in promoting personal websites and baiting readers with controversial viewpoints. The task of policing a large collaborative weblog can be enormous, requiring the dedication of community-minded moderators to remove/modify material that conflicts with the terms of service and general ethos of the site.

In Invite Only collaborative blogs the problems can become much more serious, if easier to police. While most Invite Only collaborative blogs consist of a small number of like-minded bloggers it is often the case that individuals within the group differ in opinion on divisive issues (i.e. abortion or the War on Terror). While in-fighting on these blogs can make for interesting reading it can sometimes become a problem.

Popularity

In recent years the popularity of collaborative blogs has soared. In fact, at time of writing seven of the top ten weblogs listed in N.Z. Bear's Blog Ecosystem (a popular league table of blogs based on the number of incoming links) employ collaboration of some sort.

In addition to the growth in traditional collaborative blogs the last two years has seen the emergence of a professional variety of collaboration - made up of either professional, paid commentators such as The Huffington Post (though arguably The Post does not qualify as a true blog), FilmIndustryBloggers.com or high profile bloggers engaged in a profit-sharing scheme (i.e. Pajamas Media).