Downloading BlockML 1.0 for Mac from the developer's website was possible when we last checked. We cannot confirm if there is a free download of this app available. This free software for Mac OS X is an intellectual property of Aww Apps. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe. The software lies within Productivity Tools, more precisely Office Tools.
From the developer:
BlockML is an open source markup language for complex publications, scientific work and documentation being shared on the web. It is also a minimalistic OSX app that turns plain text into HTML. BlockML combines the most useful functions of LaTeX with the simplicity of lightweight markup languages like Markdown. Some advanced features are sections, tables of contents, bibliographic references, captions, and mathematics.
You may want to check out more Mac applications, such as PitStop Extreme, 3dissue or FileOpenInstaller, which might be related to BlockML.