What is the best free blogging site?

Another vote for Posterous here. And here's what you can do to help make up your mind -- set up accounts with all the free blogging platforms. Then, set up Posterous to automatically cross-post to each of them. Try this set-up out for some time. If you decide you like a particular service more than another, then you can just continue with that one, and delete the rest, and you've wasted no time since, thanks to Posterous, they will all have the same content. If you like, keep using Posterous as your funnel -- outputting to your blog, Twitter, Flickr, Facebook, etc.

Tumblr, unless you enjoy having your content reliably indexed by search engines.

Went with Blogger (blogspot.com) for a couple of reasons... 1. Owned by Google, therefore not going anywhere anytime soon 2. Works well with Picasa, which we're using to catalog our digital images at home 3. I'm not trying to make money, so having my own domain wasn't that important, although it does have the option to point to one if you so choose 4. Tumblr looks WAY cool, but I went the "safe" route. Maybe next time! Thanks to everyone for your input. It is much appreciated!

Between the big three, you would do better to start with Blogger or Wordpress. http://foliovision.com/2008/11/17/typepad-to-wordpress is extremely difficult. It took me two years to figure out how to extricate myself from Typepad without losing my permalinks and search engine traffic. Both Blogger and Wordpress allow you to move pretty freely in and out. Make sure that whatever free service you use that you use a domain of your own and don't start your weblog on name.blogs.com or name.blogspot.com or name.wordpress.com. Later it's much harder to move your site if it's been on one of these subdomains. If your site does take off, you will want to move it from free. And sites take off slowly so you will gradually dig yourself a deeper and deeper hole if you don't set the foundations right from the beginning.

It really depends on what you want to do, but I friggin love Tumblr with all my nerdy little heart.

http://www.dreamwidth.org/ is based on an updated version of the Livejournal code. They don't have adverts, unlike Livejournal; the current Basic Livejournal accounts display banner ads to anyone who isn't a logged-in user, as well as having other accounts with more ads. You will need an invite code to create a Dreamwidth account for free; there's a link on the front page of the site to a place where you can get them.

Seconding (thirding?) Posterous.

one answer only: tumblr.

I like Wordpress. Easy enough for a beginner, but room to grow and get more complex if you eventually choose to do so.