It’s been a big week for the online music business with the announcement that the sale of legal music downloads passed the $1 billion milestone in 2005.   For all the hype, however, we should still put the online music business in context.  It’s still a small part of the overall business, just 6% of total sales for 2005.  And the gains in online sales have not matched the decline in traditional CDs and other recorded music, as the overall industry has fallen from $39.7 billion in 2000 to under $31 billion last year.  But the staggering growth rate, in which online music sales tripled from the prior year, have given hope to the recording industry that it’s finally turned the corner into the new digital world.