I have this extract of website source code:
<meta content="This is a basic text" property="og:title" />
What does this property attribute stand for, and what is its purpose?
og:title is one of the open graph meta tags. og:... properties define objects in a social graph. They are used for example by Facebook.
og:title stands for the title of your object as it should appear within the graph (see here for more http://ogp.me/ )