Blogs

I have never really looked into Blogs, but since i joined this forum i have seen a have people creating Blog designs and posting links to articles they have written, and they are all very interesting reads. I'm going to ask a bit of a stupid question here but here goes:

Is a Blog basically a personal page, where you can write whatever you want; What you done today, your opinions on things which are happening arround you, anything really....

Do most of you create your own blogs - create them like a normal website and host them by yourself. Or do you use one of the many free blog sites that are arround.

I was thinking of getting one, not sure what i would write in it yet but still...