A blog is an online diary where people share their thoughts and daily activities.
Basically u write about what u feel like! About ur family, ur hobbies, ur school, studies, ur job, ur children, ur spouse, ur political views, or celebrities or maybe promote ur business-anything u want!
Due to the easy availability of online publishing tools, even an average internet user can start a blog.
these are some free blog hosts with template and design tools and money making opportunities too,
check my profile for more information, all the best :)