It is an Excel sheet. You send data out of your of your iPhone/ iPod and get charts on your computer with Excel. (It did open in Apple Numbers but I didn't do anything in Numbers but open the sheet.) Here are the instructions for using it. From the Glooko site:
From the Glooko Logbook app, send yourself a CSV file and open the file on your computer. Download the Glooko Logbook Charts, open it in Microsoft Excel and save it to your Desktop. Click Enable Macros (on a Mac) or Enable Content (on a PC). Import your Glooko Logbook app-generated CSV file by clicking on Load New Data File and selecting your desired CSV file. Now it's time to play with your data! Set date ranges, view high and low blood glucose values, and start identifying trends.
Here is the thing. Glooko seems to me to have value because it gets data into mobile devices - those are the devices that folks keep with them all day. So pushing the charting out of the mobile device and back into a computer seems like it is going the wrong way, convenience wise.
I like the idea of visual representation of user's data. Not a fan of all kinds of jumping through hoops of exporting, sending importing and a partridge in a pear tree to get there.
I wonder if that is a function of the regulation of mobile apps on mobile and the timing of the guidance?