It has become the default Go-To (pun intended) language for me for almost anything that needs to be small and portable.
However, I don't see myself writing a full server with it, I would still prefer a dynamic language like Ruby/Python for that and use Go for micro-services CLIs and the rest.
For example:
Our main application is Rails, it communicates with SOLR as the search index, in between the application and SOLR there's a proxy server that backups the documents onto S3 and also does Round-Robin between slaves.
One other thing is that we use Go to communicate with all external APIs of 3rd parties, the application code is rails and it communicates transparently with a Go server that fetches the data from 3rd parties and responds to the main application.