Open Access Image Credit: http://bit.ly/1AVDZ6V
Open Access (OA) content, which includes open scholarly articles, open data, open research, open education, is digital, online, free of charge, and free of most copyright and licensing restrictions.
There are different ways of engaging with open access -
There are two primary vehicles for delivering OA to research articles, OA journals ("gold OA") and OA repositories("green OA"). The chief difference between them is that OA journals conduct peer review and OA repositories do not. Institutional Respositories can contain peer-reviewed journal articles that are published elsewhere. They can also contain pre-prints and post-prints of scholarly published articles.
There is also Gratis OA and Libre OA. Gratis OA removes no permission barriers and Libre OA removes one or more permission barriers. (Both of them remove price barriers.)
Why should I care?
When information is freely available, everyone wins. Researchers get all of the information they need. Students can enjoy unrestricted access to necessary educational tools. Libraries do not have to make tough choices on which journals to subscribe to. Scientists in low or middle income countries can contribute competitive research. Taxpayers can see the research they subsidize. The ones writing the research articles get more citations and see higher use of their work. Party all around!
Also, you may be required to publicly share your research. The NIH already requires that research funded by their grants be made publicly available within a year of publication. On July 29th, the Senate Homeland Security and Governmental Affairs Committee unanimously passed FASTR, the Fair Access to Science and Technology Research Act. Next it moves to the full Senate. FASTR requires all research funded by a federal agency with over $100 million in annual extramural research grants be made publicly available online. This includes the NSF, the CDC, the Department of Energy and many more.
SPARC Open Access Fact Sheet
Fact sheet on Open Access put together by Scholarly Publishing and Academic Resources Coaliton (SPARC) provides insight into impact of open access and its benefits