Wahabism is a name sometimes applied to the conservative 18th century reformist call of Sunni Islam attributed to Muhammad ibn Abd-al-Wahhab, an Islamic scholar from what is today known as Saudi Arabia, who became known for advocating a return to the practices of the first three generations of Islamic history. Wahhabism formed the creed upon which the kingdom of Saudi Arabia was founded [1] and is the dominant form of Islam found in Saudi Arabia, and Qatar,[2] as well as some pockets of Somalia, Algeria and Mauritania.[citation needed] It is now often referred to as a "sect"[2] or "branch" [3] of Islam, though its supporters reject such designations. The primary doctrine of Wahhabism is Tawhid, or the uniqueness and unity of God. [4] Ibn Abdul Wahhab was influenced by the writings of scholars such as Ibn Taymiyya and rejected medieval interpretations of Islam, relying on Quran and hadith. [5] He preached against a "perceived moral decline and political weakness" in the Arabian peninsula and condemned idolatry, the popular cult of saints, and shrine and tomb visitation. [6] The term "Wahhabi" (Wahhābīya) was first used by opponents of ibn Abdul Wahhab and is considered derogatory and rarely used by the people it is used to describe, who prefer to be called "unitarians" (Muwahiddun). [7] [8] The terms "Wahhabism" and "Salafism" are often used interchangeably, but Wahhabism has also been called "a particular orientation within Salafism," [9] an orientation some consider ultra-conservative. [10][11] (Wikipedia, of course)

As I understand it, Wahhabism is the extremely, even virulently, anti-modern, anti-western brand.

Wahhabism (originally a derogatory term used by opponents of its followers) is a movement within Sunni Islam to rid itself of cultural practices that are held to be inconsistent with the Quran. It is based on the teachings of Muhammad ibn Abd al Wahhab. You can find a great summary on: http://www.globalsecurity.org/military/world/gulf/wahhabi.htm Wahhabism is closely allied with the Al Saud Dynasty of Saudi Arabia( the founder of the Dynasty married Wahhab's daughter), and, because of this, the Saudis pour millions of dollars each year into the spread of Wahhabism into Sunni areas. One country in which you can see the "progress" of Wahhabism is Indonesia. Thirty years ago, it was rare to see a woman wearing a headscarf. Now millions of Indonesian Muslim women are covered head to foot, and sharia law is being increasingly pushed. Every year, more and more Wahhabist customs are pushed upon the Indonesian people. As a result, regional costumes are disappearing, ancient customs are being abandoned, women are retreating from public life and influence, and their rights are being restricted. The dhimmi populations, which are large, are feeling the restrictions intently, as churches are closed, women are told they cannot travel without their husbands (to attend meetings) and people are jailed for so-called proselytising, even when they have the support of the people they are "proselytising". Here are some immportant passages from the site I pointed you to above, if you do not have the time to read all of this long article: 1) To understand the significance of Muhammad ibn Abd al Wahhab's ideas, they must be considered in the context of Islamic practice. There was a difference between the established rituals clearly defined in religious texts that all Muslims perform and popular Islam. The latter refers to local practice that is not universal. The Shia practice of visiting shrines is an example of a popular practice. The Shia continued to revere the Imams even after their death and so visited their graves to ask favors of the Imams buried there. Over time, Shia scholars rationalized the practice and it became established. Some of the Arabian tribes came to attribute the same sort of power that the Shia recognized in the tomb of an Imam to natural objects such as trees and rocks. 2)His instructions in the matter of extending his religious teaching by force were strict. All unbelievers (i.e. Moslems who did not accept his teaching, as well as Christians, &c.) were to be put to death. Immediate entrance into Paradise was promised to his soldiers who fell in battle, and it is said that each soldier was provided with a written order from Ibn 'Abd ul-Wahhab to the gate-keeper of heaven to admit him forthwith. In this way the new teaching was established in the greater part of Arabia until its power was broken by Mehemet Ali. Ibn'Abd ul-Wahhab is said to have died in 1791. 3)It is clear that the claim of the Wahhabis to have returned to the earliest form of Islam is largely justified. The difference between ul-Wahhab's sect and others is that the Wahabis rigidly follow the same laws which the others neglect or have ceased altogether to observe. Even orthodox doctors of Islam have confessed that in Ibn 'Abd ul-Wahhab's writings there is nothing but what they themselves hold. At the same time the fact that so many of his followers were rough and unthinking Bedouins has led to the over-emphasis of minor points of practice, so that they often appear to observers to be characterized chiefly by a strictness (real or feigned) in such matters as the prohibition of silk for dress, or the use of tobacco, or of the rosary in prayer. 4)The Wahhabi emphasis on conformity makes of external appearance and behavior a visible expression of inward faith. Therefore, whether one conforms in dress, in prayer, or in a host of other activities becomes a public statement of whether one is a true Muslim. Because adherence to the true faith is demonstrable in tangible ways, the Muslim community can visibly judge the quality of a person's faith by observing that person's actions. In this sense, public opinion becomes a regulator of individual behavior. Therefore, within the Wahhabi community, which is striving to be the collective embodiment of God's laws, it is the responsibility of each Muslim to look after the behavior of his neighbor and to admonish him if he goes astray.