Facebook

Logo & Brand Guidelines

https://www.facebookbrand.com

Buttons & Widget

https://developers.facebook.com/docs/plugins

Developers

https://developers.facebook.com

Case Studies

https://www.facebook.com/facebookforbusiness/success

Official Blog

http://newsroom.fb.com

Twitter

Logo & Brand Guidelines

https://twitter.com/logo

Buttons & Widget

https://twitter.com/about/resources/buttons

Developers

https://dev.twitter.com

Case Studies

https://business.twitter.com/success-stories

Official Blog

http://blog.it.twitter.com

YouTube

Logo & Brand Guidelines

http://www.youtube.com/yt/brand/using-logo.html

Buttons & Widget

https://developers.google.com/youtube/youtube_subscribe_button

Developers

http://www.youtube.com/yt/dev/

Case Studies

http://www.youtube.com/yt/press/en/campaigns.html

Official Blog

http://youtube-global.blogspot.it

Google Plus

Logo & Brand Guidelines

http://www.google.com/+/business/brand-guidelines.html

Buttons & Widget

https://developers.google.com/+/web/+1button

Developers

https://developers.google.com

Official Blog

http://googleplusplatform.blogspot.it

Instagram

Logo & Brand Guidelines

http://instagram.com/press/#BrandAssets

Buttons & Widget

http://instagram.com/accounts/badges

Developers

http://instagram.com/developer

Statistics

instagram.com/press/#Stats

Official Blog

http://blog.instagram.com

Pinterest

Logo & Brand Guidelines

http://business.pinterest.com/brand-guidelines

Buttons & Widget

http://business.pinterest.com/widget-builder

Case Studies

http://business.pinterest.com/success-stories

Official Blog

http://blog.pinterest.com

Tumblr

Logo & Brand Guidelines

http://www.tumblr.com/docs/en/trademark_guidelines

Developers

http://www.tumblr.com/developers

Statistics

http://www.tumblr.com/press

Official Blog

http://lostaff.tumblr.com/

Linkedin

Logo & Brand Guidelines

http://developer.linkedin.com/branding-guidelines

Buttons & Widget

http://developer.linkedin.com/plugins

Developers

https://developer.linkedin.com

Case Studies

http://developer.linkedin.com/showcase

Official Blog

http://blog.linkedin.com