I never really got the appeal of multiple platforms. If you have a blog, you have a blog. If you don't, you don't. I started mine as a dumping ground of inspiration; a landfill of excess. Replicating that real estate only deludes the convenience of aggregation. Plus I'm a firm believer that the world only needs so much of me.
That said, if I was trying to monetize my hobby, build an image or launch a brand, I'd be everywhere and then some.