Open access publication seeks to energize authors' rights to their scholarly articles to increase access to scholarly information without barriers of paywalls or subscription requirements. 

Peter Suber, OA Champion:

"Open Access (OA) literature is digital, online, free of charge, and free of most copyright restrictions."

"The literature that should be freely accessible online is that which scholars give to the world without expectation of payment. Primarily, this category encompasses their peer-reviewed journal articles, but it also includes any unreviewed preprints that they might wish to put online for comment or to alert colleagues to important research findings.... By "open access" to this literature, we mean its free availability on the public internet, permitting any users to read, download, copy, distribute, print, search, or link to the full texts of these articles,... or use them for any other lawful purpose, without financial, legal, or technical barriers other than those inseparable from gaining access to the internet itself. The only constraint on reproduction and distribution, and the only role for copyright in this domain, should be to give authors control over the integrity of their work and the right to be properly acknowledged and cited.... Open access to peer-reviewed journal literature is the goal. Self-archiving (I.) and a new generation of open-access journals (II.) are the ways to attain this goal."

Budapest Open Access Initiative. “Read the Budapest Open Access Initiative.” Budapest Open Access Initiative, February 14, 2002. http://www.budapestopenaccessinitiative.org/read. 

What are the Benefits of Open Access to you and to Drew?

• More visibility!
  The more people who can see your publications, the more who can cite you, invite you to speak, and engage with your work!
• Improved Scholarly Landscape!
  People engaging with your work allows the entire knowledge landscape to be extended and improved. Access to your publications among non-academics allows that information to be disseminated.
• Social Justice!
  Lack of access to expensive scholarly publications is more common not just in cash-strapped institutions and unaffiliated scholars, but in the global South. For-profit publishers have been increasing the average cost of scholarly journals at approximately twice the rate of inflation (in the early 2000s, 18% a year; nowadays more like 6-7%),
  -- DeGroote, Sandy. “Subject & Course Guides: Publishing, Scholarly Communication, and Open Access: Cost of Journals.” Library Research Guides, University of Illinois at Chicago. Accessed October 23, 2017. https://researchguides.uic.edu/c.php?g=252224&p=1684825
• Control your (Scholarly) Rights!
  Open Access allows you to assert rights over your scholarly work that you might otherwise cede entirely to publishers

Figure from: 
McGuigan, Glenn S., and Robert D. Russell. “The Business of Academic Publishing.”Electronic Journal of Academic and Special Librarianship 9, no. 3 (Winter 2008). http://southernlibrarianship.icaap.org/content/v09n03/mcguigan_g01.html.

See more:

• "Open in Order To" https://oaspa.org/open-access-week-2017/
• What concrete benefits can be realized by making scholarly outputs openly available?