1) can you explain how B differs from Google Scholar? Is it a combination of Web of Science and Google Scholar approaches?
2) Going back to A, the rate of change of information doesn't actually seem to have much to do with whether information is primarily available via the public web. It is much more to do with the information culture of those who pursue the subject-- whether they value free exchange of information and whether they tend to be cheap. Stuff about librarianship, global development, computer science and, puzzlingly, physics is much more likely to be published only on the open web than medicine or business. This is because those subject areas value free exchange of information and also don't like to pay for paper publications. :)
no subject
2) Going back to A, the rate of change of information doesn't actually seem to have much to do with whether information is primarily available via the public web. It is much more to do with the information culture of those who pursue the subject-- whether they value free exchange of information and whether they tend to be cheap. Stuff about librarianship, global development, computer science and, puzzlingly, physics is much more likely to be published only on the open web than medicine or business. This is because those subject areas value free exchange of information and also don't like to pay for paper publications. :)