DocRank is a block type plugin for Moodle v2.0 made by students of the Berlin School of Economics and Law and meant to be used by schools and learning groups. It collects data on how often documents are viewed within a course and visualises the result as a chart. This enables ranking of a document's popularity and importance, urging users to read certain documents or pay closer attention to them. The chart features various filters and sortings.
The plugin directory must be moved into .../moodle/blocks/. There are several ways to achieve this.
You can install directly from the Moodle plugins directory. To do this, log into your Moodle as admin, go to Site administration > Plugins > Install plugins and click the button 'Install plugins from Moodle plugins directory'. Search for the plugin and click the install button.
You can also use the Install plugins page to upload and install the plugin after you have downloaded it from the Moodle plugins directory. Simply drag and drop the ZIP file containing the DocRank directory into the given field, or use the 'Choose a file...' button.
Alternatively, you can do it manually. Download the ZIP from the Moodle plugins directory, unzip it and move or copy the uncompressed folder into .../moodle/blocks/. Then, log into your Moodle as admin and go to Settings > Site administration > Notifications. You should get a notification about a new plugin beeing installed.
For more in-depth step-by-step instructions about installing block plugins, see 
If this plugin is active and was installed correctly, you'll see a new block in your moodle course. Clicking the logo will open a new tab with a diagram in your browser.
There are several display and sorting options, accessible via the elements above the chart.
You can change the amount of documents shown in steps of 5, from a minimum of five up to the actual number of documents in the course. The chart will automatically resize itself to accommodate for the additional bars.
The documents can be sorted either by the amount of clicks they recieved or by upload date. Use the arrow buttons to toggle between ascending and descending order.
The names of the documents, displayed to the left of their coresponding bar, double as links to the documents themselves.
By hovering your cursor above a bar, you can see the exact amount of clicks.
The plugin feeds data from the Moodle database to jqPlot