Why Cluster Genealogy? How can it help you with researching Greek ancestor's

The research technique named Cluster Genealogy can be especially helpful to those of us doing research on our Greek immigrant ancestors.  Many of them arrived in the United States, Canada, Australia or other countries, and immediately lived in neighborhoods with other Greeks, many times a relative.  

My paternal grandmother lived with her three brothers.  When I found her on the 1920 Census I was able to find her sister and husband living in the same building and a cousin living next door.  

My maternal great-grandfather has been elusive.  After a very long search, I finally found him on a passenger list, but nothing after that.  I know he lived in the Greek Delta, Chicago's Old Greek Town, but since he was probably a boarder, I can't seem to locate him.  I am planning to use this Cluster Genealogy research technique to see if I can find additional information about him. 

Following is an excerpt from  GUS'S GENEALOGY BLOG - April 10, 2010

Why Cluster Genealogy? 
Even if you don't really care who your ancestors siblings, cousins and associates were, cluster genealogy can still be a very effective research technique:

The records of siblings, cousins, and other family members may provide clues to the next generation that you haven't been able to find in the records left by your direct ancestor.

Neighbors may actually turn out to be relatives. Family groups often migrated to the same town, lived near each other, attended the same school or church, and were buried in the same cemetery.

Knowing and recognizing the names of other family members can sometimes help you locate your own ancestor when he has been missing on an index or had his name mangled in a record where you expect to find him, such as the census.

Tracking ancestors as they move from place to place can often be a daunting task. Knowing the names of relatives and neighbors who may have moved with him can make it easier to identify him in a new location.

Researching more people means an increased chance of making connections and possibly sharing research with other genealogists.

How Cluster Genealogy Works 
The cluster genealogy technique involves expanding your genealogy search beyond your direct line ancestors to include their brothers, sisters, aunts, uncles, cousins, neighbors and friends. Check for as many of these individuals as time and finances will allow in major records, including birth, marriage and death records; census records; land deeds; published family histories, etc. Collect information on them just as you do for your direct ancestors. . . "