Description of issue:
Acoording to https://www.w3.org/TR/2014/REC-html5-20141028/document-metadata.html#the-meta-element:
"“The meta element represents various kinds of metadata that cannot be expressed using the title, base, link, style, and script elements.”
URI information can be expressed using a <link href="" /> element, therefore must be represented in this manner.
This may seem overly strickt, but as a webdeveloper I have noticed I am running into compatibility issues with schema.org more and more often. schema.org and markup validators of w3c, google and yandex throw errors or warnings at the use of a URL though meta content. Schema.org calls the use of meta contant for URI’s invalid (rightfully so). As a result, schema.org requires seperate code to express the same thing on the page:
<meta name="twitter:image" content="example.com/image.png" />
<link itemprop="image" href="example.com/image.png" />
It becomes a mess, some indexers mark it as duplicate data, some mark it as invalid html. The trueth is both are the case here.
The issue is: twitter requires the use of meta, against the spesification, while other (exept facebook with opengraph! but I will file a report there too.) are not following the standard.
Do note that on a link element, a name attribute can not be used, and instead a property must be set.
Twitter might be a big platform, and its examples have been implemented on many sites, but it should not come up with its own rules on how to use HTML. It will eventually cause conflicts, like it is now doing for me.
I propose implementing support for the proper form, and leaving the improper form valid for the coming years, marking it as depreciated.
