Though Plone wasn't conceived as a blogging platform, its role as a full-fledged content management system gives it all the functionality of a blog and more. With a few well-placed tweaks, it can present an interface that puts users of other blogging packages right at home while letting you easily maintain ties between your blogs and the rest of your site.
Generally speaking, blog entries are…
Prominently labeled by date and organized in reverse chronological order
Tagged by subject
Followed by reader comments
Syndicated using RSS or other protocols
Plone provides all of these, with varying degrees of polish, out of the box:
News items make good blog entries, and the built-in News portlet lists the most recent few, in reverse chronological order and with publication dates prominently shown. A more comprehensive, paginated list can easily be made using collections.
Categories are a basic implementation of tags.
Plone's built-in commenting can work on any content type, News...