Webs: Invisible and 2.o
Here is how useless I am: I never think about the "invisible web." Actually, that's not entirely true, sometimes I think about it while I'm at the Reference Desk. I think about the ways in which the library online catalog and the databases are so much more specifically useful and generally harder to use than the "Google-web." This vague musing has never, however, progressed to wanting to do something about this, or wondering at the algorithmic structures and limitations underlying web searches. I tend to just habituate and take what I get. So I've been kind of participating in a digital dual-citizenship born of ignorance. Like Persephone in Hades, I spend half my time Googling acquaintances and shopping for boots on the "Publicly Indexable Web" and the rest of my time "underground" on subject specific, password protected "invisible" databases.
Ru and Horowitz observe the difficulty and necessity of making the "invisible web" accessible to the average user. They observe invisible web indexes usually either index the surface of the website, or index a portion of the contents of the site. Both of these approaches have the disadvantage of relying primarily on human indexing, which is subject to the subjective experience and preferences of the person doing the indexing...
The Notess article "The Terrible Twos" was helpful to me in that it gives a context to the proliferation of 2.0's in the information world. Notess describes the idea of "Web 2.0" as a simple way of conceptual differentiating the current incarnation and capabilities of the Internet from previous iterations. He includes a discussion of some of the technology that has influenced and been influenced by 2.0, including Ajax and Apis. Certain concepts identified with Web 2.0 including tagging, clouds, "the long tail," wikis, blogs, RSS feeds, etc. are easily extensible to other branches of information science, including news and of course, libraries. The idea of "Library 2.0" must certainly be a fairly limited play on the "Web 2.0" idea, as libraries have been through so many "versions" they must be on the 100.0's at least by now.
I am of a divided mind about the usefulness of 2.0 as a way of conceptualizing the different ways we use the web or libraries, or anything, today. I think the term is valuable and should certainly be "kept" http://en.wikipedia.org/wiki/Web_2.0#Criticism because it is currently in use among information professionals, who evidently feel the need to call the newest web something...My ambivalence about the term comes from my feeling that the Internet is so dynamic and such a work in progress it is hard to know what you're naming when you assign it a name.

