Is it going to be the Taliban brand of Shariah ??
The agreement is with Sufi Mohamed and their hope is it will end Maulana Fazlullah's (his son-in-law) (Taliban of Swat) violence and attacks against govt. interests and as well as move followers to Sufi's less extreme movement. The Shariah is not Taliban style but what is actually enforced on the street remains to be seen.
Undoubtedly ISI would be happy for Maulana Fazlullah to go focus his terror activities towards Afghanistan.