I recently visited a seemingly fairly reputable web site and was astonished to see their implementation of a two-stage trigger for their social media buttons:
(The text appears when you hover over any of the switches left of the button.)
I can only assume it's intended to mitigate, say, like hijacking, but it seems to be a complete waste of time: it doesn't matter which interface element you click on, you can still bind the like method to any interface element - namely the enabler switch.
This is not at all like Stack Exchange's up-vote timers (which prevent up-voting comments in quick succession, diluting the value of up-votes). In this case, the value of social sharing is likely markedly decreased since the value comes directly from widespread and easy sharing.
What other possible reason could there be to creating a barrier to sharing your page?