So, got a tumblr blog also. http://tumblr.sirjohn.co.uk/
Just experimenting. It’s just posts here that are pinged to tumblr for a wider audience or whatnot.
Will it replace WordPress for me? Not sure. tumblr is more of a microblog, though I don’t “blog” with WordPress much these days anyway. Most my snippets of uninteresting stuff are on twitter or Google+ mostly. Also having a bit of a social dabble on pinterest.
Also like that it’s easy to point a domain to tumblr, so presently I’m running tumblr as a subdomain with WordPress being the default for the root/www of the domain.