It looks like Plos Currents is exploring the concept of collaborative publishing, where the papers are maintained via Google Knol (a type of wikipedia but with a restrictions on editing).

I wonder if the "publish or perish" type of evaluations will ever recognize efforts spent on improving other people's publications.

Note also that unlike (so far as I am aware) the rest of the PLoS journals, these publications don't have a traditional anonymous peer review mechanism:

First, each section of PLoS Currents is run by a group of expert researchers — the Board of Reviewers led by two or three Editors. This group reviews all submissions and determines as rapidly as possible if the conception, structure and presentation of the submission indicate that it is a legitimate work of science and does not contain any obvious methodological, ethical or legal violations. As long as the work passes this test, it is published.

Also, I think the analogy to Wikipedia is not quite correct. They appear to be using Knol as a publishing strategy to get the "authors submit via word/latex, editor marks up, copy edits, and publishes in a different format" step out of the publication loop, but once the document is published it's citable in Pubmed Central and there is no "edit this paper" button.