Question of the day: What's the difference between a blogger and a journalist?

I regularly get invitations to press conferences/media parley.
I never go.
I always say I'm not a journalist, I'm just a blogger.
When I said this recently, someone asked me - what's the difference?
So I ask, what's the difference between a journalist and a blogger?
I have my own opinion but I want to hear yours first
Please share your thoughts