If thwarting open-access wasn’t enough, it seems that access to electronic form of classification systems is quite prohibitory. Tim writes over at the LibraryThing blog about his research into classification systems, and why he’ll likely have to go with little known classifications to do what he wants. I personally found it rather surprising that such data was that hard to get. I can see the charging for value-added services such as customized clients and workflows but keeping the data itself behind walls was a bit more than i expected.
There’s some talk in the comments on whether LC can prevent others from providing the data since it’s governmental and should be open. Regardless the post and the comments are worth a read.