Perhaps I didn't explain it as well as I could have done (or I don't fully understand Tumblr) but this would be more of an opportunity for people to put out a single post, without needing the full on "their own tumblr". I'm thinking especially people like me (and much of HN I imagine) who don't have the time to put in in maintaining a blog. With Tumblr and Posterous, you never really own the canvas either - I am looking at something whereby you can choose whether you have ads or not or you can pay etc.
Thank you though for your thoughts - it really helps.
Just a quick note to also point out, regarding this from the CEO: "if you'd like your account deleted, including all data, we're happy to do this as well."
I emailed to have my Path account deleted a few weeks ago and was told it had been 'deactivated'. After querying this, it was confirmed that they did not yet have the functionality to delete your data, only hide it. Worrying that he said they can.