Easy to use and modify but counter does not work?

I am generally happy with this plugin, and do not have page loading issues like some negative comments here. But it seems like the counters do not work properly.

I tried sharing this post [Link redacted] through facebook, twitter and google plus a bunch of times. Only the google plus counter increased by one. No increase in facebook and twitter counter. I also pretty much share all of my blog posts on my twitter account, but all my twitter counters are 0. Any known bug for that, or is there any setting I am missing?