There certainly are advantages to this approach, notably that you rich a ready made audience.
This may sound like a strange idea, but there can be considerable benefit in letting part of your blog be hosted on somebody else’s site - in their comments box. You get the benefit of a possibly wider audience - and therefore lots of attention.
Chris Paul has had a “sceptical about Tories” blog since before I started, and it is hosted in Iain Dale ’s comments box. I reckon that he gets his largest readership from this “alternative” not the real one hosted at Labour of Love; it has something like 350 entries.
My favourite practitioner of this method is probably Benji's Place, hosted by Harry's Place website.
On the subject of blogging I'm intending to revamp my links list today or tomorrow. As I'll be creating a category for sites that link here, even if they are Italian sites that I can't understand, please let me know if there are any sites that I do this which I don't already have on my sidebar.