From Closed Access...

Traditionally, journals have been sold on subscription to libraries. In the age of print-on-paper this was the only model available that enabled publishers to disseminate journals and recoup the cost. Unfortunately, this meant that only researchers in institutions that could afford to pay the subscription charges were able to read journal articles. Even wealthy universities could only afford a proportion of the world's research literature. For institutions in poorer countries this proportion is tiny or even non-existent.

... to Open Access

Now, in the age of the World Wide Web, it is possible for research findings to be disseminated free of charge to anyone who wishes to read them. This is called Open Access. Those with access to the journals in their libraries will access the articles as before - though some people say that it is actually quicker and easier to access Open Access copies through a search engine (one or two clicks) than to access the published article in a journal through their library website (which normally takes several steps). Those who do not have the journals they want in their library can use Google or other Web search engines to track down the Open Access literature in institutional and subject repositories.