The Open Access Tracking Project (OATP) < http://bit.ly/o-a-t-p
> is evolving a tag vocabulary for OA. Here are the project-approved tags to date < http://cyber.law.harvard.edu/hoap/OATP_tags
Disclosure: I'm the founder and manager of OATP, which launched in 2009. I'm not arguing that Open Science QA should use the OATP tags, merely pointing out that they've undergone 5+ years of real-world evolution and are available for use. Each OATP tag starts with an "oa." prefex, for example, "oa.journals". But the tags could be used elsewhere with or without that prefix.