The video clip The Web is Us/ing Us ( http://www.youtube.com/watch?v=6gmP4nk0EOE) was great - the description of the difference between html and xml markup language and the way xml allows you to separate out a site's content without also having to define the way that content displays was probably the most valuable part of it - that, and the very cool way it used the very same technology it was describing to describe that technology.
It's that ability to strip out the display formatting tha makes the content, or metadata, so easily exportable, mash-upable and re-combinable - and it's from that that ability to recombine that Web 2.0 emerges in all its diversity and creativity.
What it will mean for us? The digital library as a virtual branch of the NSL system is already part of the overall vision, but we can't affoard to get lazy and leave this stuff to the web team to implement on our behalf, or put them in a position where they become the technology gatekeepers - not if we want jobs ourselves in the future. Young people coming into the profession are already comfortable with this kind of technology, and what's needed now is an environment that gives those staff and patrons who want to use this technology the tools and support to make it happen in a collaborative way. That's where the true value of Web 2.0 technology in libraries comes in.
And yes, you can include the patrons in this - for a great local example of a library that does exactly that, check out Kete Horowehnua (http://horowhenua.kete.net.nz/) , a community site hosted and (very lightly) mediated by staff at Horowhenua Library.