1. how important is it to the 21 century folk revival.
2.how many other revival singers use it or find it useful
3.should it include contemporary songs[Brian informs me it does]

A1. Crucial is the first word that springs to mind. Where else is there such a comprehensive archive of English (and other) traditional song?

A2. Almost all of the revival singers I know, certainly all of the well-known English ones, have used the library's facilities, either directly by visiting or other forms of communication. For instance all of the Waterson-Carthy dynasty, The Copper Family, Shirley Collins, (no this is silly, hundreds if not thousands over the last 60 years.)

A3. This one is a matter of opinion and is more difficult to answer. However it is an interesting question and should be asked. Perhaps this one should have a thread of its own.