It's incredibly large in China (Baidu, Qiniu). I apologize since I haven't looked into countries specifically, but to respond to "anyone else seriously investing in Go?", I'll paste it here for you anyways.
Walmart, Apple, Facebook, eBay, Intel, Google, Mozilla, IBM, Microsoft, Red Hat, DigitalOcean, Zynga, Yahoo, BBC, VMware, Uber, GitHub, Getty Images, Twitter, Stack Exchange, Docker, SpaceX, Baidu, Qiniu, Imgur, CloudFlare, Bitbucket, Dell, Twitch, Dailymotion, bitly, Cisco, Verizon, Dropbox, Adobe, New York Times, HP, Canonical, Cloud Foundry, 99designs, BuySellAds, CoreOS, MongoDB, Basecamp, Rackspace, Booking, MalwareBytes, Kingsoft, Iron.io, OpenShift, Heroku, Square, Spring, Tumblr, VMWare, Symantec, Comcast, CBS, SendGrid, Digitally Imported, Pivotal, Couchbase, Koding, Shopify, Shutterfly, MaxCDN, Linden Lab, SolarWinds, IMVU, EMC, Teradata, and I'm sure many more which I'm unaware of, are all using Go to some capacity.
Walmart, Apple, Facebook, eBay, Intel, Google, Mozilla, IBM, Microsoft, Red Hat, DigitalOcean, Zynga, Yahoo, BBC, VMware, Uber, GitHub, Getty Images, Twitter, Stack Exchange, Docker, SpaceX, Baidu, Qiniu, Imgur, CloudFlare, Bitbucket, Dell, Twitch, Dailymotion, bitly, Cisco, Verizon, Dropbox, Adobe, New York Times, HP, Canonical, Cloud Foundry, 99designs, BuySellAds, CoreOS, MongoDB, Basecamp, Rackspace, Booking, MalwareBytes, Kingsoft, Iron.io, OpenShift, Heroku, Square, Spring, Tumblr, VMWare, Symantec, Comcast, CBS, SendGrid, Digitally Imported, Pivotal, Couchbase, Koding, Shopify, Shutterfly, MaxCDN, Linden Lab, SolarWinds, IMVU, EMC, Teradata, and I'm sure many more which I'm unaware of, are all using Go to some capacity.