Since 20 of November 2015 the twitter button has changed.
This is the new Twitter sharing button, as you can see there isn’t the tweets counter:
Since 20 of November the old and private endpoint that were used by the official Twitter social button at the url
http://urls.api.twitter.com/1/urls/count.json no longer works.
This means that you can’t see the count of Twitter shares within your site. Twitter explains that this was an hard decision, but it was necessary with the building of their new real time distributed system. As you can read in their blog post from Twitter there is also a question about the correct value of their counter:
This count does not reflect the impact on Twitter of conversation about your content — it doesn’t count replies, quote Tweets, variants of your URLs, nor does it reflect the fact that some people Tweeting these URLs might have many more followers than others.
A different point of view, from Italy (where Twitter is not so used), is that sharing numbers on Twitter are lowering every year, and this lead them to “stop” to show that numbers.
In any case I think this is not a good way, since it will brake a service used by a plenty of sites, apps, plugins and developers on any platform, and they will be angry with Twitter for this decision.
A solution for twitter count?
It really seems that the only way to get the Tweet counter for an URL is to do a search for your URL on Twitter, collect each page of results and add up the total number of tweets.
My Top Stories plugin at this moment doens’t make this work and will return a counter of 0 tweets. If you haven’t installed the last version (I’m going to publish it now) of the plugin it will stop and the only way to fix it is disable Twitter from the settings panel.
I’m going to wait some weeks before deciding how to handle this problem in Top Stories.
FOUND SOLUTION!: How to bring back twitter counters
More technical info, and another complex solution, can be found here.