Twitter cards would have to be enabled on the Web for this to work.

Useful links:

• Twitter Cards
• Why Wikipedia doesn't use Twitter Card

Generally, the feeling (and policy) is that Wikipedia is not a social network or an advertising platform, and services like this don't benefit a project like Wikipedia. Furthermore, using these services means that Wikipedia has to select one or more services over others, which violates its neutrality policy.

On the Dutch Project Chat a user noticed that Twitter doesn't show an image when sharing, but Facebook does. Just tested it and indeed Twitter doesn't show an image, Facebook does. Sourcecode shows an og:image metatag, but not twitter card tags.

In T170865#3516559, @NHarateh_WMF wrote:

Twitter cards would have to be enabled on the Web for this to work.

Useful links:

• Twitter Cards
• Why Wikipedia doesn't use Twitter Card

Generally, the feeling (and policy) is that Wikipedia is not a social network or an advertising platform, and services like this don't benefit a project like Wikipedia. Furthermore, using these services means that Wikipedia has to select one or more services over others, which violates its neutrality policy.

Are you sure about that Twitter cards need to be enabled? According to the link you posted Twitter supports Opengraph. We already support that for images, would be a small step to also have og:url, og:title and og:description especially now that basically every article is connected to Wikidata. I'm against implementing any social network specific tags like Twitter tags, but Opengraph ( http://ogp.me/ ) seems to be a good fit.

Wikipedia does not have card previews, because Twitter insists on you adding crap to your page to make it so. The last status on that is somewhere down in T157145: Twitter cards don't work for any projects besides Wikidata. Basically, unless you duplicate the title and description, and specify a card format, the fallbacks don't matter.

The apps used to have their own preview images that you could put text snippets onto, and these did work. Maybe people are remembering that ?