There are a bunch of new Markdown/Dropbox-based publishing tools being released lately. My favorite is http://calepin.co, but they all work similarly: Save a markdown file in a Dropbox folder and it gets published to your site.
It would be cool if MarsEdit could somehow manage those posts/files along with my Wordpress and Tumblr blogs. Seems like it would be a significant change to how MarsEdit works, but then again it might just be a slightly different way of managing "drafts." I expect it's a long shot, but I thought I'd mention it anyway.
Hi Jack - I would definitely like to adapt MarsEdit to work better with this breed of publishing tool. Currently MarsEdit has a somewhat-comparable functionality in its "Blosxom" format posts. This should work with a Dropbox-based system (MarsEdit lets you pick which folder contains the posts), but it is currently limited to only storing posts in the Blosxom-style format (folders are categories, files are posts).