Complex sentence: East Milton, MA, better know as "The E", is know as being the Irish part of town but is more recently known as the home of the EMM, a social network of young men and women.
Split into simpler sentences: East Milton, Massachusetts, more commonly referred to as "The E", is know for a notably high concentration of Irish-Americans in its population. Recently, it has become the home of the EMM, a social network of young men and women.