Over the last four centuries the Religious Society of Friends has changed greatly, to the point that one branch might hardly recognizes the validity of another. A “Great Separation” occurred in 1827 and 1828 in New York and Philadelphia Yearly Meetings followed by the remaining Yearly Meetings, dividing the Society of Friends in the USA into “orthodox” (who stressed Biblical authority) and “Hicksite” (who stressed the Inner Light) branches. Since then there have been several other divisions, especially in the orthodox branch. Quakers today differ in language, culture, and nationality. Different branches emphasize different aspects of or our tradition. Today there are five major affiliations found in the Society of Friends, Friends General Conference (representing “liberal” unprogrammed Quakers), Friends United Meeting (representing mostly mainline pastoral Meetings), Friends Evangelical Friends Church International (representing the most evangelical pastoral branch), independent Yearly Meetings and Conservative Yearly Meetings. A great deal has been written about these various branches and the causes of their separations. Quakers today are multifaceted and continue to change. Attempts to divide Friends into “programmed” verses “unprogrammed” camps while useful in the overview is simplistic. We are often more alike than we would like to admit.
Here is a worthwhile Wikipedia article about Quakerism that gives a condensed history of Friends and an overview of the different branches of Quakerism: http://en.wikipedia.org/wiki/Quakers
I would also recommend the following short Wikipedia article about Joel and Hannah Bean, who greatly influenced the development of Pacific Yearly Meeting: http://en.wikipedia.org/wiki/Joel_Bean
An excellent graphic representation of the schisms in North American Quakerism and their causes can be obtained from Friend Geoffrey Kaiser. Below is a small sample of part of this project, now on its 20th edition.
Geoffrey can send you a copy at cost if you email him at firstname.lastname@example.org.
Here is a link to an article about the chart, written by Chuck Fager for his publication Quaker Theology: http://quaker.org/quest/QT-22-Kaiser-History-Chart.html