The 4th quadrant on Dr. Daniel Siegel's system for modified meditation is about relationships with others. The teacher and author Sharon Salzberg is a specialist in loving kindness meditation. The book "The Jew in the Lotus" by Kemenetz and the book "Altered Traits" by Goleman and Davidson both emphasize the value of sending love and kindness out from the self while meditating. Before you dismiss such an idea as hokum, take a look at Prof. Davidson and his research at UW-Madison with monks from the Dalai Lama's group. Sending out love to those they love, to those they know, and to those they dislike changed the monks' brains over time.
On the other hand, I read of a situation where some group in the US found that those prayed for did a little worse recovering in the hospital than those not prayed for. I realize that prayer and meditation are not identical.
Most of my efforts at meditation have been attempts to increase my concentration and my sensitivity to what is occupying my attention. I have worked at single-point focused attention mostly, with some more open meditation observing what comes up in my mind.
Siegel's approach uses a circle divided into the four quadrants I have mentioned over the last four days but his conception has a hub in the center of the circle. He emphasizes the comparison of the hub to our awareness. In a sense, being aware that I am thinking of something IS the mindfulness that is a hot topic these days. The army, businesses, schools, athletes, cancer patients, the dying - all are finding that meditation helps a person stay open to joy, bear sadness and defeat, and all the while keep one's wits and ability to see clearly and appreciate life.