There are two basic approaches to making research findings Open Access. One is to deposit a copy of every article in an Open Access repository (this process is known as 'self-archiving') and the other is to publish in Open Access journals.
Open Access self-archiving
Authors can make their work Open Access by placing a copy of each article (along with its supporting data if possible) in an Open Access repository. These are databases of articles, datasets and other supporting research-related material. They may cover a particular discipline or subject or they may be broad-scope. Institutional repositories are usually of the latter type though there may be specialised repositories within institutions - in departments or schools or even in research groups. A repository collecting the research outputs of a university or research institute is an excellent institutional tool, as well as the means for enabling the institution's researchers to showcase their work. See much more on Open Access repositories here.
Open Access journals
Open Access journals are journals just like traditional subscription-access (Toll Access) journals except that they do not charge readers to use them. They cover their costs in other ways and publish their content online for free. Open Access journals operate like Toll Access journals in every other way, including managing the peer review process. For much more on Open Access journals, see here.
What about websites?
Sometimes, authors say that they prefer to put their articles on their own or departmental website. This is a partial solution to the problem of providing access for all, but it is not ideal. Although it is likely that Google and other web search engines will index these websites, this is not certain. Institutional repositories, subject repositories and Open Access journals all expose their contents in a particular way according to an internationally agreed standard, the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH). This enables specialised services, such as the Open Access search engine OAIster, to harvest and index the Open Access literature in a standardised way, creating databases of worldwide research. General web search engines such as Google also harvest and index the content of Open Access repositories and Open Access journals.
Author and departmental websites are also prone to be out-of-date or not fully comprehensive. And many only contain the metadata (the bibliographic details such as article title, author names, journal title and so on) of an article rather than the full text. This serves as a current awareness service but does not do what true Open Access does, which is provide access to the full text of articles for everyone to read.
Finally, institutional repositories provide much in the way of services to help showcase an author's work. They can provide usage data showing how many times an article has been downloaded, preservation services to ensure that the article and accompanying data is looked after in the long term, and other added-value services such as CV creation, citation analysis and so on. And the institution can use the repository as a management information tool. All in all, a repository provides a much more stable, comprehensive and professionalised approach to shwocasing an author's work.
Why not be more ambitious?
Many researchers have now started up Open Access journals or are publishing their work in Open Access books. Learn more about setting up an Open Access journal or ensuring your books are published with Open Access.