See the recent article in FT article
Interestingly, a Pakistan Gov official said they had to do that, because at present they don't have the technology in place to censor the internet properly, but can only block the whole site.
Abdullah Riar, Pakistan's information technology minister, yesterday said ... the government was working to refine its ability to censor the internet. It will acquire new equipment for its internet exchanges within weeks "to selectively block [more specific addresses] if those are found offensive".
"Now," he said, "we have to block the whole website because we don't have the technology to selectively block URLs."
Maybe that's the advantage Omantel brings to WorldCall!!! Oman is becoming a world leader in internet censorship. Oh dear...