Rabbi Andrea London leads Beth Emet The Free Synagogue of Evanston, Ill., which has a Facebook page.

Craig Strickland is senior pastor of Hope Presbyterian Church in Cordova, Tenn., which bills itself as a “church for the unchurched” and relies on social networking sites such as Facebook and Twitter to provide a sense of community.

Martin L. Cook is the Adm. James B. Stockdale Professor of Professional Military Ethics at the U.S. Naval War College in Newport, R.I.

Terry Ledbetter is pastor of NorthStar Church in Saltillo, Miss., which held a series of 2008 sermons on the subject of Facebook.

Kathleen Carley is a professor of organizational sociology at Carnegie Mellon University in Pittsburgh. Among her areas of study is the use of social networks

Glenn Shuck is an assistant professor in the religion department at Williams College in Williamstown, Mass. He has said that the trend of tweeting and using other social networks during religious services is likely to grow, especially among emerging churches.

The Rev. Nathan D. March created a social network site for Prince of Peace Catholic High School Youth Ministry of Lewiston, Maine, using Ning.com.

The War Resisters Support Campaign was founded in 2004 to assist U.S. military personnel who refused to participate in the Iraq war and came to Canada seeking asylum.

Mars Hill Church in Seattle uses its own social network, The City, to keep members of its several campuses connected. Mark Driscoll is pastor.