You could have downloaded Writefull 3.0 for Mac from our application library for free. The software is included in Productivity Tools. The actual developer of this free Mac application is Writefull.
From the developer:
Writefull is a free application that provides feedback on your writing. You can select a piece of text in any writing tool (from Microsoft Word to Gmail) and a small popover will appear above your selected text. This popover offers five options to assess and improve your selection with the use of the Google Books database.
You may want to check out more Mac applications, such as PDFMergeThing or iTeXMac2, which might be similar to Writefull.
Document management