via Abu Aardvark, this editorial in Al Ahram Weekly argues that salafis are rising in the middle east because political organizations like the Muslim Brotherhood have left a religious vacuum:
Wherever you look in the Arab world, Islamist conservatism of the brand known as “Salafist” is gaining ground while moderates seem to be running out of steam. Even regional satellite television stations seem more interested in conservatives than in the mainstream or opposition moderates. Also, many social institutions have fallen into the hands of the Salafis.
[...]
The Muslim Brotherhood and other moderate groups are losing their appeal before the Arab public, perhaps because they are focussing on politics and neglecting religion. And mainstream religious organisations, such as Al-Azhar and Muslim youth societies, are not doing so well either. No wonder Salafis are sidling up to centre stage. If anything, this is a moment of truth for moderates. Either they connect once again with the public, or they embrace irrelevance.

