One of the many sharing options available via Shareaholic is not a sharing service at all, but rather a service that turns the content on your pages into a printer-friendly version for easy and clean paper printouts!
This is a convenient way to have printer-friendly versions of your site content without needing to do custom programming, all powered from within the Shareaholic Share Buttons. See the printer friendly button on the far right of these sample Shareaholic buttons:
If you are using the PrintFriendly button on your site, you are actually connecting to a 3rd party service: PrintFriendly. Similar to how sharing via Facebook or Pinterest will connect to Facebook or Pinterest in order to function properly, the PrintFriendly button does the same thing. Clicking the PrintFriendly button will "share" your page to PrintFriendly. This enables a pop-up interface with a version of the page that has been stripped-down to make it tidy and clean for printing.
If you are having trouble with the format and layouts from the PrintFriendly service, please refer to their helpful Include or Exclude Content guide to make sure that your pages are set up correctly for printing. Elements can be specified to be included or excluded from your page templates, which allows you to optimize how the button works for all of your visitors/readers.
For additional documentation see the general PrintFriendly Support Documents regarding what can or can't be done with the service.