Link unfurling is a term used to describe the process of turning a plain url into a rich preview. The word was first used by Slack to describe their rich previews and it fits really well - the original definition is “to spread out from a rolled or folded state”.
Previews are useful for users to decide whether it's worth clicking and can save them a lot of time. Rich previews have quickly become an expected feature of social networks, forums, chat applications and anywhere that user generated content could include links to external websites.
PageMunch understands http, html and various other microformats in order to provide the highest quality data available. Some of the data formats parsed by PageMunch include:
The API will also handle direct file links, invalid html, badly formatted tags, invalid urls and many more edge cases to ensure the preview data is as correct as humanly possible.