Blogs come in all different shapes and sizes–you might say that there can be a blog for everything. When they first appeared, their content was mainly text-based, similar to something of a public diary where bloggers could type up whatever they wanted and publish it with the push of a button. Blogging has since evolved, incorporating photo, audio and video material, and it has also expanded into the corporate world, with many businesses and organizations promoting their products and services, or managing some internal operations through public or private blogs.
A lot of blogs are in fact personal "diaries" with no single particular topic, whereas others might be specialized in certain areas (politics, entertainment, hobbies, etc). Many people like the convenience of blogging, but don’t care too much about designing their own blogs from scratch. They can take advantage of the free blog hosting and other services, such as blog templates, offered by sites like Wordpress (see "Free Hosting" tab above).
Now that most businesses have an online presence, many of them have also successfully gotten into blogging, using business blogs to advertise their brand and the products and services they offer, and even private blogs for internal matters and communications. There are also some fake blogs out there, which purport to be "reviews" for certain products but are really internal marketing tools of the companies that make or distribute them.
There are also multimedia blogs out there for entertainment purposes, usually containing extensive photo and video material (they are also known as photoblogs and videoblogs). Blogging has made the sharing of text, sounds and images easier and more accessible than ever before.