> And those implementations are probably not covered by the patent, so it's fine.

I think what the grandparent is saying is that those implementations count as prior art and this application should have been rejected. It is ridiculous to even insinuate that the it is possible that thing that I cannot continue doing the thing I have been doing for decades because someone patented it a decade or two after I started doing it.

Did someone say they couldn't keep doing it? I don't see why they would count as prior art, either. The implementations are different from what was patented.

From my understanding, prior art doesn't haven't to be exactly the same as the invention. The invention just has to be obvious in light of the prior art. In this case, the point is that Facebook's use is obvious, given all the other similar ideas used far before.