I'm curious. Let's say I am using MarsEdit. And let's say that I switch to a new webhost and set WordPress up on it. Can I then point my MarsEdit entry at the new host URL for my site and have MarsEdit synch everything up and be up and running there without missing a beat?
Hi - although this would be a nice feature, it's deliberately *not* something that MarsEdit is good for. It's based in the limitations of the various blog APIs, not being reliable enough to "completely" archive a blog for restoration.
I always recommend that instead of MarsEdit people use the blogs' own export/import functionalities. These are designed exactly for this purpose. In this case you would export from Blog A, import to Blog B, then set up Blog B as a new blog in MarsEdit, to make sure everything is working to your satisfaction apart from Blog A.