The word 'blog' is short for 'weblog'. It's a web page made up of frequently updated, chronological diary entries that are usually quite short.

Often blogs are very personal views about a variety of topics, including commentary about other sites, world events, personal news, diaries, photos, essays, poetry and fiction.

One of the world's first blogs was Robot Wisdom, owned by Jorn Barger who also created the word 'weblog'.

Probably the most famous blog site is Blogger where you can set up your own free online journal.

Read more about blogs in The Guardian.