Enlightening the Current Scenario in Pakistan
Here, Zaid Hamid errs in failing to make a distinction between Takfiris and Salafis.
Takfiris by definition "... have been classified by some commentators as violent offshoots of the Salafi movement, yet while Salafism is seen as a form of 'fundamentalist Islam', it is not an inherently violent movement and does not condone terrorism. Takfiris, on the other hand, condone acts of violence as legitimate methods of achieving religious or political goals. Takfiris practice a number of beliefs that separate them from the Salafist movement. The most obvious example is the aforementioned labelling of fellow Muslims as kufr and the practice of declaring takfir upon them. This belief allows Takfiris to justify the use of violence against fellow Muslims; a contemporary example being the sectarian violence perpetrated in the Iraqi Insurgency."
Going by the above definition, the sectarian militias operating in Pakistan i.e. the Kurram Agency Sunni Vs Shia lashkars, Mangal Bagh's Lashkar-e-Islam Vs the Barelvi Ansar-ul-Islam in Khyber Agency, the Punjabi Lashkar-e-Jhangvi / Sipah-e-Suhaba Vs the Shia Sipah-e-Muhammad are Takfiri groups whom consider each other Kafirs - while the Afghan/Pakistan tribal militias plus the Arabs/Uzbeks operating in Afghanistan are Salafis Vs foreigners whom they consider 'Kafir' crusaders.
Another important distinction between Takfiris and Salafis is that "many Takfiris are not bound by the usual religious constraints regarding wearing a beard, drinking alcohol, or eating pork when such restrictions would interfere with waging effective jihad. To Takfiris, strict adherence to those laws precludes necessary covert action in defense of Islam." The Central Asian Jihadis would fall in this category e.g the Uzbeks and the Chechens.
Thus, above description would not place the Tehreek-e-Taliban Pakistan nor Swat's Mullah Fazlullah amongst Takfiris. It is possible though that the severity of action against the Salafi leadership of Lal Masjid, turned many Salafis into Takfiris, and this is where it now stands.
But he's right on the dot that similar groups have been emerging regularly at critical junctures in Islam, such as the formidable Khwarij movement and the Hashishin of Hasan Al Sabah, which could not sustain for long and were ultimately sidelined by the mainstream Islamic forces.