I discovered Unpaywall in a session on open knowledge in HE. Unpaywall is a Google Chrome extension that allows you to skip the paywall on millions of peer-reviewed journal articles. It’s fast, free and legal.
You will need Google Chrome to install the Unpaywall extension in your browser. The extension works by automatically looking for a copy in the Unpaywall index of over 10 million free, legal full-text PDFs. If Unpaywall finds one, a green tab will appear on your screen and you will be able to read the article. If it’s grey, Unpaywall hasn’t found the full text.
Try it for yourself here or download the extension and browse for open articles on the web.