Both types of blogs have lots of features and they are both free so get one of each and try them out.
With each of these it only takes a few minutes to start publishing your own content. The hardest part is deciding what topics you want to cover and writing the content.
Here is a getting started guide for blogger.
Here is a Start Blogging Online link on some very good but slightly advanced items for improving your blog – some are only relevant if you have your own site. How to Start a Free Blog has some other good tips.
How to start a blog begins with a theme and then choice of blog service.
This article by Kathy Sierra is actually applicable to writing or presentations in general but it is also relevant to blog posts.
Easiest instructions for starting a blog. Why is this at the end?