Link: http://markedapp.com/ →

I just discovered Marked today. It adds one of the few things I still miss from TextMate to vim, a live preview window for markdown.

Just add this to your vimrc and you can <leader>m in any markdown buffer to see a rendered preview:

autocmd FileType markdown,liquid nnoremap <buffer> <leader>m :silent !open -a Marked.app '%:p'<cr>