A recent SmartMoney article describes a recent trend toward the development of “affinity communities”–retirement communties based on shared interests.  The most common type of affinity community is a college community,  which is often located on or near a college campus and offers housing to retired faculty and alums.  Other affinity communities are designed to attract musicians and music lovers, recreational vehicle enthusiasts, nudists, asian-americans, or gays and lesbians.  Senior housing is one of the few bright spots in this dismal housing market.   Developing a senior affinity community allows a developer to stand out from what is becoming a crowded market.