Are you asking for best blogging platforms in SEO point of view or you are asking for the blog names which allow dofollow links in their comments?

while coming to the blogging platforms, i do recommend blogger and wordpress. And coming to the dofollow blog list, follow are the few which i know:

amanaryan.com
techeogi.net
live.iencyclopedia.org
aandycandy.com
mohith.net

Best Blogging Site is Blogger for Google Ads. But if you talking a best blogging site then wordpress is best

Blogger and wordpress both are good to use.

I agree with you guys, blogger, WordPress, tumbler that are some of the power sites for blogging.

It tags the web page with keywords so that user could understand the contents before downloading it for them. You can register on a social bookmarking site to help you save these web address, store bookmarks and add tags.

Very nice collection shared by you. I was just searching this type of collection and luckily I got it from your blog. I like your blog also. And i share to some high pr site..

Wordpress
Blogger
Tumblr
Posterous
Twitter
Xanga
Weebly

wordpress and blogger
trellis