^^^
The likes, it use a small extra bit of script (a socalled Google api, used for web apps), and loads from a different location than the forum itself.
Which explains why the forum may work and the likes part sometimes being delayed or unavailable.
With adblocks, tracking blockers, Noscript etc, the script for the likes may be blocked. It's safe to allow it, Google may harvest an anonymous entry about someone somewhere used their api, but they harvest 100.000's times more info about anyone through 10.000's much more effective channels.