[daremon]

"...that will increase speed by around 80%..."

I guess this is compared to plain PHP not to accelerators? And what exactly is the difference from a PHP accelerator?

[Confusion]

I think it is quite irrelevant to wonder about such details, as the article proceeds to spout nonsense like

   The project is very similar to Google's Unladen Swallow
   project, which rebuilt the Python compiler, boosting the
   speed fivefold [..]

There is not a word to be trusted, as the author clearly doesn't know what he is talking about.

[pvg]

The typical PHP accelerators cache bytecode rather than native code.

[FooBarWidget]

Yes but I wonder how much it will really help. Is the bottleneck for Facebook-like sites really in the bytecode dispatching as opposed to e.g. string/regexp operations or database calls?