I have seen the term Iceberg related to genealogy research a few times over the years. There was a poster put out by in 2009 by The California Genealogical Society and Library.
This week Lenore from The GenTraveling Site left a comment on one of my posts so I headed over to her site where I found her definition of an Iceberg Genealogy Researcher. (Follow the link)
Take a look at her description. Does it describe some of your genimates?