To protect your privacy while at the same time providing an easy way to interact with us, we have implemented the two-click privacy implementation from the publisher heise from Germany. If you are interested in the details, you can read the original article (german).
The basic concept is easy: We initially present a simple image loaded from our servers. Upon the first click, the real social network integration is loaded, i.e. a facebook 'like' button. At this stage, the social network knows that you have visited a site with integration to this network.
With a second klick, you can then interact with the social network just as you are used to.
Right now, we have implemented that on the download site (http://download.pdfforge.org). The social icons on this page are simple links that point to the respective social network. They don't have any background interaction at all.
We hope that you appreciate the privacy features. If you do and want to share us nonetheless, you can try out the new two-click feature ;-)