Opt-in social media
The browser plug-in 'Ghostery' shows which websites other than the one you are visiting know that you are loading the webpage. In the case of petitions this can be quite an infringement in the privacy. Consider the situation where someone is using a workstation at work to visit a petition page (even without signing) about an issue that is problematic for the employer and this is communicated to third parties (Facebook, Google, etc.) Later on, while browsing the web together with a coworker on the same workstation advertisements appear related to that controversial petition.
Besides this, parties like Facebook can create a duplicate of our database of signatories simply by tracking who visits the signature confirmation page. Even those without Facebook will be in there. Probably with more information about them than they consciously fill in because all their behaviour can be combined.
The solution is simply. Only load social media icons fully after clicking on them. This will also speed up loading the page. Each icon is slightly shaded, greyed out. Clicking on them makes them bright, in full colour and only then a connection with that party is made. And only that one. E.g. when you click on the LinkedIn icon, no information is sent to Facebook.
This solution is invented by Heise in Germany in 2011 according to this page and was later called the Shariff project and has it's own GitHub entry.