Like mentioned in the post above, if your article content, site, or Facebook application are new, it can take a few days for the Like button to fully work properly.
You can use the Linter tool, below, to scan individual pages that are having the issue. Once scanned, they should start working automatically. I did it with the page you linked, and now the Like count is working as expected:
developers.facebook.com/tools/lint
Facebook will scan your pages automatically with time, but the Linter is good to kick-start the process. You won't have to do this with each new page forever.
Hope this helps, and let us know if you run into any other issues!
Alex