The term blog comes from web log. A web log is traditionally a site that has regular entries or post of either news, commentary, videos or pictures. Blogs are usually updated regularly with new material that is visible on the home page of the site. Many times blogs are managed and owned by a single person but you also have company blogs or gossip blogs that are edited by several people. There are blogs by genres that can include politics, traveling, music, art, food, and whatever else you can thinks of.
Within the blogosphere (the online community of bloggers) there are many blogs that use the social network of blogrolls or backlinks to boost their blog popularity and many times you will see blog sites posting advertisements for such companies as Crate and Barrel. Blogs can become a source of income for some people, but with over 100 million blogs it is becoming increasingly difficult to have a niche blog that is unlike any other.
So basically a blog is an online journal. And this journal can be about anything.
A blog can also be an ecommerce site, plenty of ecommerce shopping sites are now based upon popular blogging software.
Here’s an example of 3 sites that are wordpress blogs – you would never even know it!
Shisha Tobacco (ShishaHookah.co.uk)
Casinos (Casinos.org)
Colon Cleansing (coloncleansingadvisor.com)