About filtering Wikipedia or any other website in the Gaza Strip - Gaza doesn't have its own telecommunication infrastructure. Even though the Palestinian Authority has reserved its own international dialing prefix (+970), and its own TLD (.ps), in practice, the telecommunication infrastructure is operated from Israel (the +972 zone). There are special numbers and dialing codes reserved for the use of the Palestinian Territories, and as far as I know, this applies for the Internet access too. I don't know if it is possible technically to intervene in the transmission of information, while the "hub" is beyond your territory, especially as Hamas has no official status. For these purposes, it communicates with the world through the PA, if and when it is willing to do the service (they cooperate if it's for the benefit of the local Gazan residents). Anyway, that's the best account I can offer about this unusual situation.

Dror K