This is a theme component that will allow you to easily add extra social providers to the share button on posts.


Repository Link
https://github.com/discourse/discourse-social-share

Preview: https://theme-creator.discourse.org/theme/Dax/social

Samples

image: 494x219, 75%

Settings:

image: 690x276

English Social Media

Tumblr. https://www.tumblr.com/share/link?url=
Pinterest: https://pinterest.com/pin/create/button/?url=
Linkedin: https://www.linkedin.com/shareArticle?mini=true&url=
Reddit: https://reddit.com/submit?url=
AddThis: https://www.addthis.com/bookmark.php?url=
GetPocket: https://getpocket.com/edit?url=
Evernote: https://www.evernote.com/clip.action?url=
HackerNews: https://news.ycombinator.com/submitlink?u=
[s]StumbleUpon https://www.stumbleupon.com/submit?url=[/s] Replaced with mix.com
Digg: https://digg.com/submit?url=
FlipBoard: https://share.flipboard.com/bookmarklet/popout?v=2&title=
InstaPaper:https://www.instapaper.com/edit?url= (currently European users can not access because of the GDPR)
Flattr: https://flattr.com/submit/auto?user_id={user_id}&url=
Diaspora: https://share.diasporafoundation.org/?title={title}&url=
Viber: viber://forward?text=

Non-English Social Media

QzSahre:http://sns.qzone.qq.com/cgi-bin/qzshare/cgi_qzshare_onekey?url= (chinese)
Weibo: http://service.weibo.com/share/share.php?url= (chinese)
Douban: https://www.douban.com/recommend/?url= (chinese)
RenRen: http://widget.renren.com/dialog/share?resourceUrl= (chinese)
Vk: https://vk.com/share.php?url= (russian)
OKru: https://connect.ok.ru/dk?st.cmd=WidgetSharePreview&st.shareUrl= (russian)
Xing: https://www.xing.com/app/user?op=share&url= (german)
SurfingBird: http://surfingbird.ru/share?url=

Phone/Audio-Based Social Media

SMS: sms:{phone_number}?body=
Telegram: https://telegram.me/share/url?url=
LineMe: https://lineit.line.me/share/ui?url=
Skype: https://web.skype.com/share?url=
WhatsApp: https://wa.me/?text=
WhatsApp Web: https://web.whatsapp.com/send?text= (read also https://meta.discourse.org/t/social-share-component-with-whatsapp-web/108684/11?u=dax)

This guide is a wiki, if you have other providers, maybe specific for your country, just add them to the list.
You will find the share URL in the documentation for the developers.