Blogs!!!

Today we learned about blogs and how to create a blog. For once i was totally clueless about them. Why have blogs in the first place??? What are they used for?? I suppose in one sense they are fun as you can write whatever you want on it, but then again what do you write about?? The daily news, your life story, people you like and do not like etc.. How do you begin??
Hopefully i will figure out someday and will be able to write something instead of a whole load of rubbish!!!