A blog, also known as weblog is a website that publishes articles and posts, written by a group or an individual using straight text, photographs or images (photoblog), video (videoblog), audio (audioblog) and hyperlinks.

Blogs are mostly used for online journal or a web diary, content management system and online publishing platform. They are usually arranged in reverse chronological order.

A typical blog has the components such as title, main body, post date, labels, RSS, trackback, comments, permalinks and other optional items.

There are different types of blogs. The following are some of them:

1. Political blog - on news, politics, activism, etc.

2. Personal blog - also known as online diary

3. Topical blog - with focus on a particular niche

4. Health blog - on specific health issues

5. Literary blog - also known as litblog

6. Travel blog - with focus on a traveler's stories

7. Research blog - on academic issues such as research

8. Legal blog - on law and legal affairs; also known as 'blawgs'

9. Media blog - exclusive for a newspaper or a television network

10. Religious blog - on religious topics

11. Educational blog - usually written by students and teachers

12. Collaborative or collective blog - written by a group of people

13. Directory blog - contains a collection of blogs and web sites

14. Business blog - used by entrepreneurs and corporate employees

15. Personification blog - focus on other than humans

16. Spam blog - used for promoting affiliated websites; also known as 'splogs'