There are many different types of blogs, differing not only in the type of content, but also in the way that content is delivered or written.
Personal blogsThe personal blog, an ongoing diary or commentary by an individual, is the traditional, most common blog type. Personal bloggers usually take pride in their blog posts, even if their blog is never read by anyone but them. Blogs often become more than a way to just communicate; they become a way to reflect on life or works of art. A type of personal blog is referred to as "microblogging," which is extremely detailed blogging as it seeks to capture a moment in time. Sites, such as Twitter, allow bloggers to share thoughts and feelings instantaneously with friends and family and is much faster than e-mailing or writing. This form of social media lends to an online generation already too busy to keep in touch.
Corporate blogs
A blog can be private, as in most cases, or it can be for business purposes. Blogs, either used internally to enhance the communication and culture in a corporation or externally for marketing, branding or public relations purposes are called corporate blogs.
Question blogging
Is a type of blog that answers questions? Questions can be submitted in the form of a submittal form, or through email or other means such as telephone or VOIP. Question blogs (Qlogs) can be used to display shownotes from podcasts or the means of conveying information through the internet. Many question logs use syndication such as RSS as a means of conveying answers to questions.
Group blog
A blog type with more than one regular contributing writer. Also known as a collaborative blog. Like the name says, it’s a blog that’s controlled by several people. Basically, a few people get together and share the workload. One of the main benefits is that each person will be able to bring there strengths into the mix. Everyone can share their ideas for monetizing the site and increasing the revenue. Also, everyone can share there knowledge of Search Engine Optimization (SEO), and other promotion strategies.
CeleblogA blog written about celebrity or written by a celebrity. Usually focuses on news, gossip and often contains embarrassing or revealing paparazzi photos.
Movlogs
These are mobile video blogs. These are similar to a Moblog, but the feature videos.
Media BlogThey can be video blog, music (mp3) blog, or photo blog. Their blog posts are shorter as their main focus is to share multimedia contents.
SplogA spam blog.
Tech blog
A blog that focuses on new technology information.
LinguablogAbout linguistics, translation etc.
MetablogThis is a blog type about blogging.
MilblogA military blog.
Project BlogA blog dedicated to a specific project. This can range from a hobby project to a larger corporate project.
BlawgBlogged by lawyer/related to legal stuff.
Edu-blogEducation oriented blog.
PhotocastA photoblog that automatically updates when new photos are added.
MicroBlog
A blog that allows up to 140 character long posts. Twitter is the most popular and allows text messaging for blog postings via cell phone.
Those are the most commonly used types of blogs on the Internet today. There are some more blog types there.