Six decades ago Clifford Geertz wrote perhaps the most famous work on heterogeneity in Islam. As Islam evolved in two distinct "civilizations" (to use his term) in Morocco and Indonesia, it developed quite distinct characteristics and practices. For Geertz, while Islam was still identifiable as a single religious tradition, its practices in Morocco and Indonesia diverged significantly, almost to the point of being different religions. Islam Observed has been the gold standard ever since for arguments about heterogeneity among diverse Muslim communities. Globalization and the information revolution of recent decades have reversed some of the trends Geertz pointed to and, indeed, have been forces for greater homogenization across diverse Muslim landscapes. For example, Salafism, which is a historically foreign form of Islam in Southeast Asia, is now a growing trend, fed by forces of globalization and information flows from the Middle East to Southeast Asia. This paper begins to outline some of the important forms of recent homogenization in Islam, focusing on the importation to Southeast Asia of some practices and beliefs from the Middle East, Saudi Arabia in particular. The paper argues that while Geertz was accurate in his assessments from 60 years ago, important globalization dynamics have reversed his findings in important ways ever since. The paper is based on fieldwork in Malaysia, Indonesia, Singapore and Brunei during four months in 2019.