my first thought was "Cool! Damn, not markdown." Security issues aside I think you'd addressed the use case for the "common man" well. I (and I think many of the geeks here) would prefer a markdown variant though. No selecting and clicking to bold things, no reaching for the mouse, etc. That being said, a the ability to bold and italicize without leaving the keyboard are pretty standard text editor features at this point that ZenPen would do well to incorporate and the functionality would be reusable in a markdown variant too.