Actually, I just did a fairly extensive search on Google using "Danny Boy" as keywords.

The actual text referred to (ie Michael Robinson's and Melody Net) seems to be the virtual urban legend at this point. A couple of other sites mention Michael Robinson as their source. Other than that, there is nothing verifiable from over 450 sites I just viewed.

However, I found some astoundingly interesting things, like an Ulster Loyalist website claiming it is a Protestant/Loyalist song, which also appears to be the only site with enough cheek to have what may well be pirated versions of Elvis' and Eric Clapton's versions of Danny Boy!

Also, this Internet legend version of "facts" about this song also seem to only be concerned with the history in England of the song, and it's connections to Irish politics.

However, when you look at who has actually recorded this song, you see a STRONG line of African American artists who have covered it, from early jazz players, to Paul Robeson, to the Blind Boys of Alabama, to Wycliffe Gordon.

Since the "Internet legend has it" that the tune was mailed to an English man from his American sister-in-law, and seeing how deep the roots of the tune are in the African American music traditions, I'd say there is likely a whole lot more to this song/tune than Michael Robinson has included on his web page!