By the looks of it, nothing more at the moment than smoke and mirrors.
If I was so inclined, I could have the code rebranded, setup a similar website, and call it the WORLDPBX project, all within a twenty four hour period.
If you are going to do a fork, and keep the community interested and accepting, from day 1, you provide a very clear roadmap, and in most cases, why there is a need for a fork, explaining very clearly the shortcomings of the project that it has been forked from.
So far on that site, the roadmap and reason for the fork appears to approximate no more than one line.
It appears that the person has been excited by the recent Mambo/Joomla fork, which is even more evident that the Website is developed under Joomla (Mambo), and wants the same excitement with his/her fork. The difference was that the issues with Mambo were reasonably well known beforehand, from day 1 they provided very clear roadmap and reasons, and as such almost all thirdparty developers have committed to Joomla.
Now, that all said, everyone is welcome to try their hand, and one of the great concepts of the open source world is that bigger and better products may evolve. If that happens with OPENPBX, well done to that person or group.
Anyhow just my take, everyone else is welcome to their views.