Journals, articles or aggregators?

info NeoGnostic: Russian dolls: containers in containers

Here is an interesting "debate" between Carol Tenopir and Stevan Harnad (both published in Nature on this topic) about the unit of publication in the future. Will it be the article, the journal or (as info NeoGnostic thinks) the aggregator? An issue of much concern to scientific (and other) journals, not least Nature, which is a commercial operation.
It seems to be emerging that the place where the information is held is less important. In the scientific community, the "open access" debate of a few years ago focused on the exhortation by people like Harnad that publishers should not have access restrictions or, if they refuse, authors should co-publish their work in an open archive (this debate was revisited more recently). The PLOS (public library of science) journals launched on the back of this philosophy, backed by multi-million dollar charitable endowment in the absence of a viable business model.
But Google’s activities (Google Scholar mainly) seem to have rendered the archive as such somewhat moot, or at least will do in future as GS comes out of beta and is refined into a more accurate, quantifiable information-retrieval tool. What will be the important thing is the access restriction itself, and not the place where the information is held.
The challenge for publishers such as Nature Publishing Group, Elsevier, PLOS, AAAS et al. will be to come up with more and more added-value features to attract people to their sites rather than search engines. Or something using not-yet-developed technology to get people to look at the content they have published so that they can gather revenue from the viewing. This is where the aggregation comes in, which of course includes "secondary" content (reviews of the literature and news/opinion about science).
In the meantime, the main performance indicator used by the scientific profession, the "impact factor" (about which books could and probably have been written), is also up for grabs, with Google Scholar potentially providing a challenge to the main player in this market, the Institute for Scientific Information (ISI), and Elsevier’s relatively new product, Scopus.