Forum Moderators: mack
There are three options which some to mind:
a) Web Logs (Blogs)
b) Wiki's
c) Full blonw Content Management Systems (CMS)
The order reflects the level of complexity, and - from my point of view - the available options in design and look&feel of your website.
I personlly use the open source Typo3 CMS, which can be run in "front end editing" mode where you can do actual in-place editing of the live system. In the back-end editing you also work on the live system, but you have more influence on the design.
I haven't tried a Wiki yet, but the popular wikipedia project shows what's possible with this rather new concept. It seems to be the ideal mix of CMS and BLOG for a certain type of websites.