The beauty of HN is that this is pretty much the only place where you can meet the person with exactly the same exotic nerdy problem. I am thinking about moving from TiddlyWiki on Dropbox to Simplenote that (IIRC, at least when you pay) can synchronize notes to Dropbox, has a native iPhone app and a whole roster of 3rd party clients for other mobile OSs and desktop clients (http://simplenote.com/downloads/).