An expatriate, or "expat", is someone living temporarily or residing permanently in a country and culture other than that of their origins. It can also be one living in a country and/or culture other than that which they are a citizen of.
Wikipedia defines the word as coming from "the Latin ex (out of) and patria (country, fatherland), and is sometimes misspelled (either unintentionally or intentionally) as ex-patriot or short ex-pat (because of its pronunciation)."
Expatriate can just as well be used to describe any person living in a country other than where they hold citizenship, but is generally not used for government officials stationed in a foreign country.
Genexpat serves those that feel they are part of a "new" lost generation. Those that feel rootless or unbelonging in their place of birth.
While I'm a Gen X'er, Genexpat goes beyond a generational demographic. It's more a representation of all those who feel a wanderlust or the need to leave their native country for political, financial - such as taxation, economic opportunity, cultural differences, or just worldly curiousity.
While Europeans or North Americans living in the certain parts of South American, the Middle East and Asia often wed local people and start families, many do not become citizens of their adopted countries. Often it is due to dual nationality restrictions. However, they may adopt permanent resident status.
Again from wikipedia:
"The so-called "expatriots," a term referring to United States American literary notables who lived in Paris from the period which saw the end of World War I to the beginning of the Great Depression, included people such as Ernest Hemingway, F. Scott Fitzgerald, T. S. Eliot, Ezra Pound, and Gertrude Stein. African-American expatriation to Paris also boomed after World War I, beginning with black American veterans who preferred the subtler racism of Paris to the oppressive racism and segregation in parts of the United States."
"In the 1920s African-American writers, artists, and musicians arrived in Paris and popularized jazz in Parisian nightclubs, a time when Montmartre was known as "the Harlem of Paris." Some notable African-American expatriates from the 1920s onward included Josephine Baker, Langston Hughes, Richard Wright, James Baldwin, Miles Davis, and Charlie Parker. "
"Another famous group of expatriates was the so-called Beat Generation of American artists living in other countries during the 1950s and 1960s. This group included Allen Ginsberg, William S. Burroughs, Harold Norse, Gregory Corso and Gary Snyder. Later generation expatriates also included 1950s jazz musicians such as Steve Lacy, 1960s rock musician Jim Morrison, and 1970s singer-songwriter Elliott Murphy."