Google - the core Go team work at Google. Most uses of Go at Google are confidential. The YouTube team have released their MySQL scaling infrastructure as open source software. And dl.google.com is written in Go: mailing list discussion / OSCON slides. Other known uses include the Turkey Doodle (2011), the Santa Tracker (2012), writing map/reduce jobs, Jam With Chrome, the CubeSlam Chrome Experiment, and the pprof command line tool.
10gen - blog
6Wunderkinder - video
99designs - golang-nuts
ActiveState - github
adeven - blog github
Airbrake - blog
Apcera - blog
Aruba Networks - golang-nuts
BBC Worldwide - source
Beachfront Media article
Betable - talk #1, talk #2
Bitbucket - source
bitly - github blog
Canonical - source
Carbon Games - source
CloudFlare - blog article
Cloud Foundry - blog github
CloudWalk - github
clypd - blog
Conformal Systems - blog post github
Crashlytics - tweet
Cupcake - tweet github
CustomerIO - tweet
Digital Ocean - blog
Disqus - blog
DNSimple - blog
domainr - tweet
dotCloud - docker slides
drone.io - post github
Dropbox - blog, github
Embedly - blog
ErrPlane - blog
Foize - github
Flipboard - source (job post)
Getty Images - tweet tweet
GitHub - blog post
Globo.com - github article
GOV.UK - slides github blog
Granify - blog
Hailo - slides
Heroku - Go blog post
Intel Germany (Debugger QA Team) - source
Iron.io - source blog:“30 servers to 2” blog:“2 years of production Go”
JelloLabs - blog
Jimdo - tweet github
Koding - quora
Lincoln Loop - blog (as part of https://botbot.me/ , #go-nuts IRC logging)
New Bamboo - blog
MaxCDN - blog
Microcosm - slides
Modcloth - github
Moovweb - github source
Mozilla Services - github blog
MROffice - source
New York Times - source
ngmoco:) - blog
Novartis - g+ post
Ooyala - github
Oyster Books - blog
Percona - blog
Plano Bê - podcast
pool.ntp.org - blog status
Poptip job posting
Rawstream - tweets
Raygun - blog
Rendered :Text - blog
Repustate - blog
Rounds - blog
Secret - blog
SendGrid - blog
SendHub - source (shipbuilder PaaS)
Shopify tweet
Showyou source
SmartyStreets source
SmugMug - blog
Skimlinks blog
SoundCloud - blog
Sourcegraph github
Space Monkey - blog
Splice - tweet
Square - blog
StatHat - Go blog post
Steals.com blog
Streetspotr - tweet
Stretchr github
SyndicatePro - source
Tamber - blog
The Plant - Developing Qortex, a social productivity application, and backend infrastructure using Go. source
Thomson Reuters Eikon - github source
Thumbtack - Go Hercule blog post
TinkerCad
Toggl - blog
Torbit - blog
Tumblr - github source
Twitch - blog
TweetQureet - blog
Undisclosed.ch - github
Urlist - tweet
Viki - github
VividCortex - source github
Zynga - source (zbase component) github