Yes, anyone can view them while using a web browser
All blogs created in all blogging platform are by default made public.There is however an option to make them private or restrict their views to some members of your family
TRUE
Assuming it's a public blog and not an internal company blog anyone will be able to view the blog.
Unfortunately this is currently unavailable as a public document. I can tell you that there are over 10,000 blogs created on blogger alone.
blogs
blogs
Corporate blogging can be viewed on external public blogs. Corporate blogs are written primarily for consumers or for other businesses. One of the most popular corporate blogs is the official Google Blog.
Some disadvantages of web logs, or blogs, include the potential for lack of credibility and reliability as anyone can create and publish a blog without rigorous fact-checking. Additionally, blogs can sometimes lack privacy as they are often public and can be accessed by anyone. Lastly, maintaining a successful and popular blog requires consistent time and effort, which may be a challenge for some individuals.
Most blogs are available to use (write) from the age of 13 an up. Anyone at any age can read the blogs that are posted on the internet.
to criticize the public's response
Wordpress is a great place for people to share and read blogs, and has become very popular for its great features. These features include allowing anyone from Facebook, Twitter, and WordPress to comment, quicker photo loading, get notifications together from all of ones blogs, even on a mobile device, and promote anything published using social media sites.
If by "blogs" you mean from Blogger.com, then no, they are all open to the public. However, you may change the options for that while either creating a blog (it asks you while you make it), or simply click "customize".
WordPress Mu is for those who want to have a website that allow other people to register and build their blogs in the site. Allowing others to build blogs is the key difference between Wordpress Mu and Wordpress.