Software or CMS used for Top 20 blogs.
The top blogs as ranked by Technorati use a mixture between third party software such as WordPress and that developed and maintained primarily by internal engineers, such as the system used by Gizmodo.
Cms
10 Facts about Blogs.
Ø What are “Blogs”?
A “Blog”- shorthand term that means “Web log”—is an online, chronological collection of personal information, commentary and links Easy to create and use from anywhere with an Internet connection.
Blogs are a form of Internet publishing that has become an established communications tool.
According to Wikipedia
A blog (or weblog) is a type of website or part of a website. Blogs are usually maintained by an individual with regular entries of commentary, descriptions of events, or other material such as graphics or video.