Specifically on songs
I believe Steve Gardham's statement on information is spot on regarding the access to information
The Irish Famine (1845-1850) was Ireland's greatest catastrophe - at least one million dead and another million were left wih no other alternative but to emigrate - that emigration goes on to the present day.
Up to the 150th anniversary of the event there was one serious study of the subject, by an Englishwoman (The Great Hunger, Mrs Cecil Woodham Smith 1962).
Until Independence in 1922 the news was heavily influenced by British colonial interests and after independence, by the Irish need to maintain friendly relations with her English neighbors for the purposes of keeping the door open to the continuing flow of emigrants.
There were few songs made about the Famine while it was occurring, ("people were too busy dying") but the period from 1798 to the middle of the 20th century is rich in historical accounts of Irish life, from its politics to everyday living - songs about emigration represent the largest number in the folk repertoire, next to love songs   
As I said on the other thread, to quote a 90 year old farmer/singer we recorded a couple of years ago, "In those days, if a man farted in church, somebody made a song about it"
That to me, puts the importance of songs, as entertainment and as carriers of information, in a nutshell
Jim Carroll