Based on all feedback gathered during the RfC about a possible inter-project links interface [1], User:Tpt has created a content card prototype (image: [2])

To activate it, follow these steps:

Go to your common.js file. For a user named "Test" in English Wikipedia, it would be: https://en.wikipedia.org/wiki/User:Test/common.js
Modify it and paste this line: mw.loader.load('//www.wikidata.org/w/index.php?title=User:Tpt/interproject.js&action=raw&ctype=text/javascript');
Save and go to any Wikipedia page
You should see an icon next to the article title, if you don't, refresh your browser cache. Instructions: Internet Explorer: hold down the Ctrl key and click the Refresh or Reload button. Firefox: hold down the Shift key while clicking Reload (or press Ctrl-Shift-R). Google Chrome and Safari users can just click the Reload button.

What it does:

It displays an icon next to the article title
When you hover your mouse over the icon it shows a content card.
The content card displays information from Wikidata: label, image, link to Commons gallery, and link to edit Wikidata.

What it is supposed to do in the future when Wikidata supports sister projects:

It will display contents or links to sister projects

Please leave your feedback on the Request for comments, thanks!

http://meta.wikimedia.org/wiki/Requests_for_comment/Interproject_links_interface#Comments

Cheers,
Micru

[1] http://meta.wikimedia.org/wiki/Requests_for_comment/Interproject_links_interface
[2] http://commons.wikimedia.org/wiki/File:Content-card-prototype.png