Why do I use WordPress instead of a TYPO3 extension?
A friend of mine put it like this:
It’s hard to make a blog out of TYPO3
as it is hard to make WordPress a CMS
This pretty much nails it ;) There are many extensions out there like T3BLOG, timtab, news and comments extensions and also a blog_example. But believe me, you will not be able — at least now — to get a blog up and running faster than with WordPress. Everything else is a big pain. Endless typoscript configurations, the old subpart / marker syntax, unmatched dependencies between extensions and so on … And we didn’t talk about search engine optimization up to this point.