I have three blogs that show the same stuff hosted with different companies. You ask why go through this trouble. The reason is simple. If someone asks me to pay I could move to the other. Or if someone does something i don't like or asks me to jump through all the hoops i just delete that blog and move to the other one. And that way i will not loose my blog and its entries.
I am also getting indexed more. Microsoft can't ignore spaces blog and google can't ignore blogger blog. So when you look at it, its really useful.
I know what you are going to ask, do i go and post on all the blogs, no i use a program called windows live writer which post to all the three blogs but i have to go and select each blog account and publish it. its like posting three stories for one story but in the long run i think it will be worth it.
If you want to read the same stuff on the other sites go here