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.

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.

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

The Catholic Diocese of San Jose, Calif., uses Facebook and Twitter to stay in touch with local Catholics.

Holy Cross Evangelical Lutheran Church of Fairfield, Ohio, uses Facebook to connect with its members and lists that under the church’s ministries. The church also links to the ELCA’s Imagine Yourself social network. Timothy R. Swanson is reverend.

Southwest Christian Church in East Point, Ga., uses its Facebook page for a variety of things, including evangelization.

Cornerstone Chapel of Leesburg, Va., uses Facebook and Twitter to reach its members throughout the week. Gary Hamrick is senior pastor.